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  • 1.
    Anoshkin, Ilya V.
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Lioubtchenko, Dmitri V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Freeze-Dried Carbon Nanotube Aerogels for High-Frequency Absorber Applications2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, ISSN 1944-8244, Vol. 10, no 23, p. 19806-19811Article in journal (Refereed)
    Abstract [en]

    A novel technique for millimeter wave absorber material embedded in a metal waveguide is proposed. The absorber material is a highly porous carbon nanotube (CNT) aerogel prepared by a freeze-drying technique. CNT aerogel structures are shown to be good absorbers with a low reflection coefficient, less than -12 dB at 95 GHz. The reflection coefficient of the novel absorber is 3-4 times lower than that of commercial absorbers with identical geometry. Samples prepared by freeze-drying at -25 degrees C demonstrate resonance behavior, while those prepared at liquid nitrogen temperature (-196 degrees C) exhibit a significant decrease in reflection coefficient, with no resonant behavior. CNT absorbers of identical volume based on wet-phase drying preparation show significantly worse performance than the CNT aerogel absorbers prepared by freeze-drying. Treatment of the freeze-dried CNT aerogel with n- and p-dopants (monoethanolamine and iodine vapors, respectively) shows remarkable improvement in the performance of the waveguide embedded absorbers, reducing the reflection coefficient by 2 dB across the band.

  • 2.
    Asadollahi, Ali
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. KTH.
    A Study of Surface Treatments and Voids Formation in Low Temperature Wafer BondingManuscript (preprint) (Other academic)
  • 3.
    Baghban, Mohammad Amin
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Schollhammer, Jean
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Errando-Herranz, Carlos
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gylfason, Kristinn B.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gallo, Katia
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Waveguide Gratings in Thin-Film Lithium Niobate on Insulator2017In: 2017 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC), IEEE , 2017Conference paper (Refereed)
  • 4.
    Banovic, Vladimir
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Real-Time Monitoring of Neurovascular Cells2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Organs-on-a-chip devices are perfused cell culture systems aimed at creating the minimal functional unit of an organ - suchas the neurovascular unit (NVU) of the brain. NVU-on-a-chip platforms can provide an effective framework for studyingcentral nervous system physiology, disease etiology and provide a mean for drug development.In this work, we investigated the possibility of developing NVU-on-a-chip devices, with real-time sensing capabilitiesof glucose - intended for monitoring the metabolic activity of neurovascular cells. This was done by evaluating theperformance and applicability of in-house ultra-miniaturized glucose sensor technology and commercial DropSence (DS)electrodes, as well as studying astrocytoma characteristics.Firstly the performance of the amperometric microsensors was assessed - demonstrating a sufficient linear detectionrange (6, 2±0, 7 mM) for monitoring normal glucose levels of the brain (0, 5−1, 5 mM) and a high sensitivity (0, 09±0, 02mA/mM/mm2) . Limit of detection (LOD) ranged between 0, 04 mM for the 3_2 model microsensor to up to to 0, 14±0, 05mM for the DS electrodes. Limit of detectable change (LO4S), obtained from deviations between repeated measurements,was found to be approximately 0, 6 mM for all the sensors - close to the normal glucose concentrations of the brain. Limitof detectable change (LO4N), obtained from signal-noise within single measurements, was smallest for the biggest DSelectrodes (0, 04 mM).Secondly the compatibility of sensor materials (substrate and functional membranes) with astrocytoma cells was tested.Cell viability and growth, in conjunction with test materials, were assessed and compared to that of glass and/or cellculturetreated polystyrene (plastic). The materials tested were: Nafion; polyurethane (PU); Glucose Oxidase/bovineserum albumin/glutaraldehyde (GOx/GA); and silicon substrate with SiO2 surface. Cell viability and growth provedalmost as good on nafion membrane as on plastic and glass, while the enzyme containing layer proved to be toxic - mostlikely due to the protein-reactive crosslinker glutaraldehyde. PU-membrane showed significantly lower performance thanglass but demonstrated the best ability to encapsulate the toxic effect of the innermost enzyme layer. In contrast, nafioncoverage resulted in a lack of cells adjacent to the membrane - suggesting partial permeability to the harmful compoundsof the innermost layer. The SiO2surface of the silicon substrate, demonstrated significantly lower performance than plasticin terms of cell viability and growth.Thirdly glucose uptake rates of astrocytoma cell were determined. Depending on glucose availability in the the test wellsthe cells demonstrated a wide range of uptake rates: between 6, 5 · 10

  • 5. Beck, O.
    et al.
    Kenan Modén, N.
    Seferaj, S.
    Lenk, Gabriel
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Helander, A.
    Study of measurement of the alcohol biomarker phosphatidylethanol (PEth) in dried blood spot (DBS) samples and application of a volumetric DBS device2018In: Clinica Chimica Acta, ISSN 0009-8981, E-ISSN 1873-3492, Vol. 479, p. 38-42Article in journal (Refereed)
    Abstract [en]

    Phosphatidylethanol (PEth) is a group of phospholipids formed in cell membranes following alcohol consumption. PEth measurement in whole blood samples is established as a specific alcohol biomarker with clinical and medico-legal applications. This study further evaluated the usefulness of dried blood spot (DBS) samples collected on filter paper for PEth measurement. Specimens used were surplus volumes of venous whole blood sent for routine LC–MS/MS quantification of PEth 16:0/18:1, the major PEth homolog. DBS samples were prepared by pipetting blood on Whatman 903 Protein Saver Cards and onto a volumetric DBS device (Capitainer). The imprecision (CV) of the DBS sample amount based on area and weight measurements of spot punches were 23–28%. Investigation of the relationship between blood hematocrit and PEth concentration yielded a linear, positive correlation, and at around 1.0–1.5 μmol/L PEth 16:0/18:1, the PEth concentration increased by ~ 0.1 μmol/L for every 5% increase in hematocrit. There was a close agreement between the PEth concentrations obtained with whole blood samples and the corresponding results using Whatman 903 (PEthDBS = 1.026 PEthWB + 0.013) and volumetric device (PEthDBS = 1.045 PEthWB + 0.016) DBS samples. The CV of PEth quantification in DBS samples at concentrations ≥ 0.05 μmol/L were ≤ 15%. The present results further confirmed the usefulness of DBS samples for PEth measurement.

  • 6.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Low-Loss Silicon Micromachined Waveguides Above 100 GHz Utilising Multiple H-plane Splits2018In: Proceedings of the 48th European Microwave Conference, Madrid, October 1-3, 2018, 2018Conference paper (Refereed)
    Abstract [en]

    For sub-millimeter and millimeter wave applications rectangular waveguides are an ideal transmission medium. Compared to conventional, metal-milled rectangular waveguides, silicon micromachined waveguides offer a number of advantages. In this paper we present a low-loss silicon micromachined waveguide technology based on a double H-plane split for the frequency bands of 110 – 170 GHz and 220 – 330 GHz. For the upper band a reduced height waveguide is presented, which achieves a loss per unit length of 0.02 – 0.10 dB/mm. This technology has been further adapted to implement a full height waveguide for the lower frequency band of 110 – 170 GHz. The full height waveguide takes advantage of the benefits of the double H-plane split technique to overcome the challenges of fabricating micromachined waveguides at lower frequencies. With measured insertion loss of 0.007 – 0.013 dB/mm, averaging 0.009 dB/mm over the whole band, this technology offers the lowest insertion loss of any D-band waveguide to date. The unloaded Q factor of the D-band waveguide technology is estimated to be in excess of 1600, while a value of 750 has been measured for the reduced height upper band waveguide.

  • 7.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Micromachined Waveguides with Integrated Silicon Absorbers and Attenuators at 220–325 GHz2018In: IEEE MTT-S International Microwave Symposium, IEEE conference proceedings, 2018 / [ed] IEEE, IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    This paper reports for the first time on micromachined waveguides with integrated micromachined silicon absorbers. In contrast to epoxy-based microwave absorbers, micromachined lossy silicon absorbers are fully compatible with high temperature fabrication and assembly processes for micromachined waveguides. Furthermore, micromachining enables the fabrication of exact, near ideal taper tips for the silicon absorbers, whereas the tip of epoxy-based absorbers cannot be shaped accurately and reproducibly for small waveguides. Silicon of different conductivity is a very well understood and characterized dielectric material, in contrast to conventional absorber materials which are not specified above 60 GHz. Micromachined silicon waveguides with integrated absorbers and attenuators were designed, fabricated and characterized in the frequency band of 220 – 325 GHz. The return and insertion loss for various taper-geometry variations of double-tip tapered absorbers and attenuators was studied. The average return loss for the best investigated device is 19 dB over the whole band. The insertion loss of the two-port attenuators is 16 – 33 dB for different designs and shows an excellent agreement to the simulated results. The best measured devices of the one-port absorbers exhibit an average and worst-case return loss of 22 dB and 14 dB, respectively, over the whole band. The return loss is not characterized by a good simulation-measurement match, which is most likely attributed to placement tolerances of the absorbers in the waveguide cavities affecting the return but not the insertion loss.

  • 8.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Beuerle, Bernhard
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Krivovitca, Aleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Low-Loss Hollow and Silicon-Core Micromachined Waveguide Technologies Above 100 GHz2018Conference paper (Other academic)
  • 9.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gomez-Torrent, Adrian
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Krivovitca, Aleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Bolander, Lars
    Ericsson Research.
    Li, Yinggang
    Ericsson Research.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. KTH Royal Institute of Technology.
    An Ultra Low-Loss Silicon-Micromachined Waveguide Filter for D-Band Telecommunication Applications2018Conference paper (Refereed)
    Abstract [en]

    A very low-loss micromachined waveguide bandpassfilter for use in D-band (110–170GHz) telecommunication applicationsis presented. The 134–146GHz filter is implemented in a silicon micromachined technology which utilises a double H-plane split, resulting in significantly lower insertion loss than conventional micromachined waveguide devices. Custom split-blocks are designed and implemented to interface with the micromachined component. Compact micromachined E-plane bends connect the split-blocks and DUT. The measured insertion loss per unit length of the waveguide technology (0.008–0.016 dB/mm) is the lowest reported to date for any micromachined waveguide at D-band. The fabricated 6-pole filter, with a bandwidth of 11.8 GHz (8.4%), has a minimum insertion loss of 0.41 dB, averaging 0.5 dB across its 1 dB bandwidth, making it the lowest-loss D-band filter reported to date in any technology. Its return loss is better than 20 dB across 85% of the same bandwidth. The unloaded quality factor of a single cavity resonator implemented in this technology is estimated to be 1600.

  • 10.
    da Silva Granja, Granja
    et al.
    Loughborough University.
    Sandström, Niklas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Efimov, Igor
    Loughborough University.
    Ostanin, Victor P
    Cambridge University.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Klenerman, David
    Cambridge University.
    Ghosh, Sourav
    Loughborough University.
    Characterisation of particle-surface interactions via anharmonic acoustic transduction2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 272, p. 175-184Article in journal (Refereed)
  • 11.
    Demchenko, P.
    et al.
    ITMO Univ, St Petersburg 197101, Russia..
    Gomon, D.
    ITMO Univ, St Petersburg 197101, Russia..
    Anoshkin, Ilya V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Lioubtchenko, Dmitri
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. ITMO Univ, St Petersburg 197101, Russia..
    Khodzitsky, M.
    ITMO Univ, St Petersburg 197101, Russia..
    Influence of optical pumping on properties of carbon nanotubes with different geometric parameters in THz frequency range2018In: 2018 43RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ), IEEE , 2018Conference paper (Refereed)
    Abstract [en]

    Impact of infrared radiation illumination (980 nm) on the properties of cabon nanotubes (CNT), such as complex conductivity and permittivity, with different geometric parameters (lengths, diameters and with presence/absence graphene oxide layer) in the frequency range of 0.2-1.0 THz was studied.

  • 12.
    Dubois, Valentin
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Crack-junctions: Bridging the gap between nano electronics and giga manufacturing2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Obtaining both nanometer precision of patterning and parallel fabrication on wafer-scale is currently not possible in conventional fabrication schemes. Just as we are looking beyond semiconductor technologies for next-generation electronics and photonics, our efforts turn to new ways of producing electronic and photonic interfaces with the nanoscale. Nanogap electrodes, with their accessible free-space and connection to electronic circuits, have attracted a lot of attention recently as scaffolds to study, sense, or harness the smallest stable structures found in nature: molecules. The main achievement of this thesis is the development of a novel type of nanogap electrodes, the so called crack-junction (CJ). Crack-junctions are unparalleled at realizing nanogap widths smaller than 10 nm and can be fabricated based exclusively on conventional wafer-scale microfabrication equipment and processes. These characteristics of crack-junctions stem from the sequence of two entirely self-induced steps participating in the formation of the nanogaps: 1./ a splitting step, during which a pre-strained electrode-bridge structure fractures to generate two new electrode surfaces facing one another, followed by 2./ a dividing step during which mechanical relaxation of the elastic strain induces displacement of these surfaces away from one another in a precisely controlled way. The positions of the resulting nanogaps are precisely controlled by designing the electrode-bridges with notched constrictions that localize crack formation. Based on the crack-junction methodology, two continuation concepts are developed and demonstrated. In the first concept, the crack-junction methodology is extended to electrode materials that are ductile, rather than brittle. This led to the development of a new type of break junction, the so called crack-defined break junction (CDBJ). In the second concept, the crack-defined nanogap structures realized by the crack-junction methodology are utilized as a shadow mask for the fabrication of single nanowire devices. The optical-lithography-compatible processes developed here to produce high-density arrays of individually-adjusted crack-junctions, crack-defined break junctions, and single-nanowire devices, provide viable solutions to bridge 10−9 nanoelectronics and 109 giga manufacturing.

  • 13.
    Dubois, Valentin J.
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Raja, Shyamprasad Natarajan
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gehring, Pascal
    Delft Univ Technol, Kavli Inst Nanosci, Lorentzweg 1, NL-2628 CJ Delft, Netherlands..
    Caneva, Sabina
    Delft Univ Technol, Kavli Inst Nanosci, Lorentzweg 1, NL-2628 CJ Delft, Netherlands..
    van der Zant, Herre S. J.
    Delft Univ Technol, Kavli Inst Nanosci, Lorentzweg 1, NL-2628 CJ Delft, Netherlands..
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. KTH Royal Inst Technol, Sch Elect Engn & Comp Sci EECS, Dept Micro & Nanosyst MST, SE-10044 Stockholm, Sweden..
    Massively parallel fabrication of crack-defined gold break junctions featuring sub-3 nm gaps for molecular devices2018In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, article id 3433Article in journal (Refereed)
    Abstract [en]

    Break junctions provide tip-shaped contact electrodes that are fundamental components of nano and molecular electronics. However, the fabrication of break junctions remains notoriously time-consuming and difficult to parallelize. Here we demonstrate true parallel fabrication of gold break junctions featuring sub-3 nm gaps on the wafer-scale, by relying on a novel self-breaking mechanism based on controlled crack formation in notched bridge structures. We achieve fabrication densities as high as 7 million junctions per cm(2), with fabrication yields of around 7% for obtaining crack-defined break junctions with sub-3 nm gaps of fixed gap width that exhibit electron tunneling. We also form molecular junctions using dithiol-terminated oligo(phenylene ethynylene) (OPE3) to demonstrate the feasibility of our approach for electrical probing of molecules down to liquid helium temperatures. Our technology opens a whole new range of experimental opportunities for nano and molecular electronics applications, by enabling very large-scale fabrication of solid-state break junctions.

  • 14.
    Dubois, Valentin
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Massively parallel fabrication of crack-defined gold break junctions featuring sub-3 nm electrode nanogapsIn: Article in journal (Refereed)
  • 15.
    Enrico, Alessandro
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Dubois, Valentin
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Scalable fabrication of single nanowire devices using crack-defined shadow mask lithographyIn: Article in journal (Refereed)
  • 16.
    Errando-Herranz, Carlos
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Edinger, Pierre
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. KTH Royal Institute of technology.
    Colangelo, Marco
    KTH.
    Björk, Joel
    KTH.
    Ahmed, Samy
    KTH.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gylfason, Kristinn B.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    New dynamic silicon photonic components enabled by MEMS technology2018In: Proceedings Volume 10537, Silicon Photonics XIII, SPIE - International Society for Optical Engineering, 2018, Vol. 10537, article id 1053711Conference paper (Refereed)
    Abstract [en]

    Silicon photonics is the study and application of integrated optical systems which use silicon as an optical medium, usually by confining light in optical waveguides etched into the surface of silicon-on-insulator (SOI) wafers. The term microelectromechanical systems (MEMS) refers to the technology of mechanics on the microscale actuated by electrostatic actuators. Due to the low power requirements of electrostatic actuation, MEMS components are very power efficient, making them well suited for dense integration and mobile operation. MEMS components are conventionally also implemented in silicon, and MEMS sensors such as accelerometers, gyros, and microphones are now standard in every smartphone. By combining these two successful technologies, new active photonic components with extremely low power consumption can be made. We discuss our recent experimental work on tunable filters, tunable fiber-to-chip couplers, and dynamic waveguide dispersion tuning, enabled by the marriage of silicon MEMS and silicon photonics.

  • 17.
    Fan, Xuge
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Wagner, Stefan
    Faculty of Electrical Engineering and Information Technology, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany.
    Schädlich, Philip
    Institute of Physics, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz, Germany.
    Speck, Florian
    Institute of Physics, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz, Germany.
    Satender, Kataria
    Faculty of Electrical Engineering and Information Technology, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Seyller, Thomas
    Institute of Physics, Chemnitz University of Technology, Reichenhainer Straße 70, 09126 Chemnitz, Germany.
    Lemme, Max C.
    Faculty of Electrical Engineering and Information Technology, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany ; Gesellschaft für angewandte Mikro- und Optoelektronik mbH (AMO GmbH), Advanced Microelectronic Center Aachen, Otto-Blumenthal Str. 25, 52074 Aachen, Germany.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Direct observation of grain boundaries in graphene through vapor hydrofluoric acid (VHF) exposure2018In: Science advances, ISSN 2375-2548, Vol. 4, no 5, article id eaar5170Article in journal (Refereed)
    Abstract [en]

    The shape and density of grain boundary defects in graphene strongly influence its electrical, mechanical, and chemical properties. However, it is difficult and elaborate to gain information about the large-area distribution of grain boundary defects in graphene. An approach is presented that allows fast visualization of the large-area distribution of grain boundary–based line defects in chemical vapor deposition graphene after transferring graphene from the original copper substrate to a silicon dioxide surface. The approach is based on exposing graphene to vapor hydrofluoric acid (VHF), causing partial etching of the silicon dioxide underneath the graphene as VHF diffuses through graphene defects. The defects can then be identified using optical microscopy, scanning electron microscopy, or Raman spectroscopy. The methodology enables simple evaluation of the grain sizes in polycrystalline graphene and can therefore be a valuable procedure for optimizing graphene synthesis processes.

  • 18. Ghosh, Sourav K.
    et al.
    Sandström, Niklas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ostanin, V.P
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Klenerman, D.
    Guha, A.
    Simple and ultrafast resonance frequency and dissipation shift measurements using a fixed frequency drive2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 281, p. 960-970Article in journal (Refereed)
    Abstract [en]

    A new method for determination of resonance frequency and dissipation of a mechanical oscillator is presented. Analytical expressions derived using the Butterworth-Van Dyke equivalent electrical circuit allow the determination of resonance frequency and dissipation directly from each impedance datapoint acquired at a fixed amplitude and frequency of drive, with no need for numerical fitting or measurement dead time unlike the conventional impedance or ring-down analysis methods. This enables an ultrahigh time resolution and superior noise performance with relatively simple instrumentation. Quantitative validations were carried out successfully against the impedance analysis method for inertial and viscous loading experiments on a 14.3 MHz quartz crystal resonator (QCR). Resonance frequency shifts associated with the transient processes of quick needle touches on a thiol self-assembled-monolayer functionalised QCR in liquid were measured with a time resolution of 112 μs, which is nearly two orders of magnitude better than the fastest reported quartz crystal microbalance. This simple and fast fixed frequency drive (FFD) based method for determination of resonance frequency and dissipation is potentially more easily multiplexable and implementable on a single silicon chip delivering economies of scale.

  • 19.
    Gomez-Torrent, Adrian
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Shah, Umer
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Compact silicon-micromachined wideband 220 – 330 GHz turnstile orthomode transducer2018In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446Article in journal (Refereed)
    Abstract [en]

    This paper reports on a turnstile-junction orthomode transducer (OMT) implemented by silicon micromachiningin the 220 – 330 - GHz band. Turnstile OMTs are very widebandand allow for co-planar ports, but require accurate and complex geometries which makes their fabrication challenging at higher frequencies. The compact 10 mm x 10 mm x 0.9 mm OMT-chip presented in this paper is the first micromachined full-band OMT in any frequency range, and only the second turnstile OMT implemented above 110 GHz. The measured insertion loss(0.3 dB average, 0.6 dB worst-case) and the cross-polarization (60 dB average, 30 dB worst-case) over the whole waveguide band represent the best performance of any wideband OMT, regardless of design or fabrication technology, in the 220 –330 - GHz band. The return loss with 22 dB average (16 dB worst case) is comparable or better than previous work. The paper discusses design considerations and compromises of this complex 9 layer silicon micromachined device, including the influence of sidewall slopes, underetching, and post-bonding misalignment between the chips. It is shown that for a device which is very sensitive to geometrical variations, such as a turnstile OMT, it is necessary to anticipate and compensate for any fabrication imperfections in the design to achieve high RF performance.

  • 20.
    Gomez-Torrent, Adrian
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Wideband 220 – 330 GHz Turnstile OMT Enabled by Silicon Micromachining2018In: 2018 IEEE MTT-S International Microwave Symposium (IMS), 2018Conference paper (Refereed)
    Abstract [en]

    This paper is the first publication on the first turnstile-junction orthogonal mode transducer (OMT) above110GHz, which is enabled by silicon micromachining. Incontrast to other OMT concepts, turnstile OMTs are wideband and allow for co-planar ports, but require accurate and complex fabrication and have therefore, to the best of our knowledge,not been implemented above 110GHz in any technology. As shown in this paper, the fabrication and assembly accuracy of silicon micromachining enables the realization of such complex OMT designs at 220 – 330GHz with excellent performance. The measured insertion loss is better than 0.7dB for the whole waveguide band, with mean values of 0.34dB and 0.48 dB for the vertical and horizontal polarizations, respectively. The measured return loss for both polarizations, even with an open ended common port, is better than 14dB for the whole waveguide band, and an average level of 18dB. An estimation of the worst-case cross-polarization level, derived from measurements, results in at least 20dB for the whole waveguide band, with an average of 25dB for the upper half of the band.

  • 21.
    Guo, Maoxiang
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Hernández-Neuta, Iván
    Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, Tomtebodavagen 23 A, SE-17165 Solna, Sweden.
    Madaboosi, Narayanan
    Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, Tomtebodavagen 23 A, SE-17165 Solna, Sweden.
    Nilsson, Mats
    Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, Tomtebodavagen 23 A, SE-17165 Solna, Sweden.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Efficient DNA-assisted synthesis of trans-membrane gold nanowires2018In: Microsystems & Nanoengineering, ISSN 2055-7434, Vol. 4, p. 1-8, article id UNSP 17084Article in journal (Refereed)
    Abstract [en]

    Whereas electric circuits and surface-based (bio)chemical sensors are mostly constructed in-plane due to ease of manufacturing, 3D microscale and nanoscale structures allow denser integration of electronic components and improved mass transport of the analyte to (bio)chemical sensor surfaces. This work reports the first out-of-plane metallic nanowire formation based on stretching of DNA through a porous membrane. We use rolling circle amplification (RCA) to generate long single-stranded DNA concatemers with one end anchored to the surface. The DNA strands are stretched through the pores in the membrane during liquid removal by forced convection. Because the liquid–air interface movement across the membrane occurs in every pore, DNA stretching across the membrane is highly efficient. The stretched DNA molecules are transformed into trans-membrane gold nanowires through gold nanoparticle hybridization and gold enhancement chemistry. A 50 fM oligonucleotide concentration, a value two orders of magnitude lower than previously reported for flat surface-based nanowire formation, was sufficient for nanowire formation. We observed nanowires in up to 2.7% of the membrane pores, leading to an across-membrane electrical conductivity reduction from open circuit to o20 Ω. The simple electrical read-out offers a high signal-to-noise ratio and can also be extended for use as a biosensor due to the high specificity and scope for multiplexing offered by RCA.

  • 22.
    Guo, Weijin
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gustafsson, Linnea
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Jansson, Ronnie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Hedhammar, My
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology. KTH, School of Biotechnology (BIO), Centres, Centre for Bioprocess Technology, CBioPT.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Formation of a thin-walled Spider Silk Tube on a Micromachined Scaffold2018In: Proceeding of 2018 IEEE 31st International Conference on Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2018, Vol. 2018, p. 83-85Conference paper (Refereed)
    Abstract [en]

    This paper reports on the first formation of a thin bio-functionalized spider silk tube, supported by an internal micromachined scaffold, in which both the inside and outside of the tube wall are freely accessible. The silk tube could potentially be used as an artificial blood vessel in an in vitro tissue scaffold, where endothelial cells and tissue cells can grow on both sides of the silk tube.

  • 23.
    Haraldsson, Klas Tommy
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Synthetic paper - a microstructured coating developed for medical diagnostics2018In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Article in journal (Other academic)
  • 24.
    Hauser, Janosch
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Lenk, Gabriel
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Hansson, Jonas
    Beck, Olof
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    High yield passive plasma filtration from human finger prick bloodManuscript (preprint) (Other academic)
  • 25.
    Hauser, Janosch
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Lenk, Gabriel
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Hansson, Jonas
    Beck, Olof
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    High yield passive plasma filtration from human fingerprick bloodManuscript (preprint) (Other academic)
  • 26.
    Hauser, Janosch
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Lenk, Gabriel
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Hansson, Jonas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Beck, Olof
    Karolinska Inst, Dept Lab Med, S-14186 Stockholm, Sweden..
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    High-Yield Passive Plasma Filtration from Human Finger Prick Blood2018In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 22, p. 13393-13399Article in journal (Refereed)
    Abstract [en]

    Whole-blood microsampling provides many benefits such as remote, patient-centric, and minimally invasive sampling. However, blood plasma, and not whole blood, is the prevailing matrix in clinical laboratory investigations. The challenge with plasma microsampling is to extract plasma volumes large enough to reliably detect low-concentration analytes from a small finger prick sample. Here we introduce a passive plasma filtration device that provides a high extraction yield of 65%, filtering 18 mu L of plasma from 50 mu L of undiluted human whole blood (hematocrit 45%) within less than 10 min. The enabling design element is a wedge-shaped connection between the blood filter and the hydrophilic bottom surface of a capillary channel. Using finger prick and venous blood samples from more than 10 healthy volunteers, we examined the filtration kinetics of the device over a hematocrit range of 35-55% and showed that 73 +/- 8% of the total protein content was successfully recovered after filtration. The presented plasma filtration device tackles a major challenge toward patient-centric blood microsampling by providing high-yield plasma filtration, potentially allowing reliable detection of low-concentration analytes from a blood microsample.

  • 27.
    Hauser, Janosch
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Lenk, Gabriel
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ullah, Shahid
    Beck, Olof
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    An Autonomous microfluidic device for generating volume-defined dried plasma spots (DPS)Manuscript (preprint) (Other academic)
  • 28.
    Hussain, Muhammad Waqar
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Elahipanah, Hossein
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics, Integrated devices and circuits.
    Zumbro, John E.
    University of Arkansas.
    Schröder, Stephan
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Rodriguez, Saul
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics, Integrated devices and circuits.
    Malm, B. Gunnar
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics, Integrated devices and circuits.
    Mantooth, H. Alan
    University of Arkansas.
    Rusu, Ana
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics, Integrated devices and circuits.
    A 500 °C Active Down-Conversion Mixer in Silicon Carbide Bipolar Technology2018In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 39, no 6, p. 855-858Article in journal (Refereed)
    Abstract [en]

    This letter presents an active down-conversion mixer for high-temperature communication receivers. The mixer is based on an in-house developed 4H-SiC BJT and down-converts a narrow-band RF input signal centered around 59 MHz to an intermediate frequency of 500 kHz. Measurements show that the mixer operates from room temperature up to 500 °C. The conversion gain is 15 dB at 25 °C, which decreases to 4.7 dB at 500 °C. The input 1-dB compression point is 1 dBm at 25 °C and −2.5 dBm at 500 °C. The mixer is biased with a collector current of 10 mA from a 20 V supply and has a maximum DC power consumption of 204 mW. High-temperature reliability evaluation of the mixer shows a conversion gain degradation of 1.4 dB after 3-hours of continuous operation at 500 °C.

  • 29.
    Krivovitca, Aleksandr
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Micromachined Silicon-core Substrate-integrated Waveguides with Coplanar-probe Transitions at 220-330 GHz2018In: Transmission-line structures: Advances in Millimeter-Wave Integrated Waveguide Components and Transitions, IEEE, 2018, p. 190-193Conference paper (Refereed)
    Abstract [en]

    Abstract—In this paper, we present for the first time on, to the best of our knowledge, the first silicon-core micromachined substrate-integrated waveguide (SIW) in the 220-325 GHz frequency range. In contrast to the fabrication methods used for conventional SIW known from substantially lower frequencies, micromachining allows for a full-height waveguide and near-ideal and arbitrarily shaped sidewalls. The silicon dielectric core allows for downscaling the waveguide and components by a factor of 3.4 as compared to an air-filled waveguide. At 330 GHz, the measured waveguide insertion loss is as low as 0.43 dB/mm (0.14 dB/λg, normalized to the guided wavelength). Devices were manufactured using a two-mask micromachining process. Furthermore, a low-loss ultra-wideband coplanar-waveguide (CPW) transition was successfully implemented, which comprises the very first CPW-to-SIW transitions in this frequency range. The measured transition performance is better than 0.5 dB insertion loss (average of 0.43 dB in the band above 15% above the waveguide-cutoff frequency), which is lower than previously reported CPW-to-SIW transitions even at 3 times lower frequencies, and the return loss is better than 14 dB for 75% of the waveguide band.

  • 30.
    Laakso, Miku
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Bleiker, Simon J.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Liljeholm, Jessica
    Silex Microsystems AB.
    Mårtensson, Gustaf
    Mycronic AB.
    Asiatici, Mikhail
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. EPFL École polytechnique fédérale de Lausanne, Processor Architecture Laboratory.
    Fischer, Andreas C.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. Silex Microsystems AB.
    Stemme, Göran
    KTH, Superseded Departments (pre-2005), Signals, Sensors and Systems. KTH, Superseded Departments (pre-2005), Biotechnology. KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ebefors, Thorbjörn
    Silex Microsystems AB.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Through-Glass Vias for MEMS Packaging2018Conference paper (Other academic)
    Abstract [en]

    Novelty / Progress Claims We have developed a new method for fabrication of through-glass vias (TGVs). The method allows rapid filling of via holes with metal rods both in thin and thick glass substrates.

    Background Vertical electrical feedthroughs in glass substrates, i.e. TGVs, are often required in wafer-scale packaging of MEMS that utilizes glass lids. The current methods of making TGVs have drawbacks that prevent the full utilization of the excellent properties of glass as a package material, e.g. low RF losses. Magnetic assembly has been used earlier to fabricate through-silicon vias (TSVs), and in this work we extend this method to realize TGVs [1].

    Methods The entire TGV fabrication process is maskless, and the processes used include: direct patterning of wafer metallization using femtosecond laser ablation, magnetic-fieldassisted self-assembly of metal wires into via holes, and solder-paste jetting of bump bonds on TGVs.

    Results We demonstrate that: (1) the magnetically assembled TGVs have a low resistance, which makes them suitable even for low-loss and high-current applications; (2) the magneticassembly process can be parallelized in order to increase the wafer-scale fabrication speed; (3) the magnetic assembly produces void-free metal filling for TGVs, which allows solder placement directly on top of the TGV for the purpose of high integration density; and (4) good thermal-expansion compatibility between TGV metals and glass substrates is possible with the right choice of materials, and several suitable metals-glass pairs are identified for possible improvement of package reliability [2].

    [1] M. Laakso et al., IEEE 30th Int. Conf. on MEMS, 2017. DOI:10.1109/MEMSYS.2017.7863517

    [2] M. Laakso et al., “Through-Glass Vias for Glass Interposers and MEMS Packaging Utilizing Magnetic Assembly of Microscale Metal Wires,” manuscript in preparatio

  • 31.
    Laakso, Miku J.
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Bleiker, Simon J.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Liljeholm, Jessica
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Mårtensson, Gustaf E.
    Mycronic AB, S-18353 Taby, Sweden..
    Asiatici, Mikhail
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. Ecole Polytech Fed Lausanne, Sch Comp & Commun Sci, CH-1015 Lausanne, Switzerland..
    Fischer, Andreas C.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ebefors, Thorbjorn
    Silex Microsyst AB, S-17543 Jarfalla, Sweden.;MyVox AB, S-12938 Hagersten, Sweden..
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Through-Glass Vias for Glass Interposers and MEMS Packaging Applications Fabricated Using Magnetic Assembly of Microscale Metal Wires2018In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 44306-44317Article in journal (Refereed)
    Abstract [en]

    A through-glass via (TGV) provides a vertical electrical connection through a glass substrate. TGVs are used in advanced packaging solutions, such as glass interposers and wafer-level packaging of microelectromechanical systems (MEMS). However, TGVs are challenging to realize because via holes in glass typically do not have a sufficiently high-quality sidewall profile for super-conformal electroplating of metal into the via holes. To overcome this problem, we demonstrate here that the via holes can instead be filled by magnetically assembling metal wires into them. This method was used to produce TGVs with a typical resistance of 64 m Omega, which is comparable with other metal TGV types reported in the literature. In contrast to many TGV designs with a hollow center, the proposed TGVs can be more area efficient by allowing solder bump placement directly on top of the TGVs, which was demonstrated here using solder-paste jetting. The magnetic assembly process can be parallelized using an assembly robot, which was found to provide an opportunity for increased wafer-scale assembly speed. The aforementioned qualities of the magnetically assembled TGVs allow the realization of glass interposers and MEMS packages in different thicknesses without the drawbacks associated with the current TGV fabrication methods.

  • 32.
    Ladhani, Laila
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    An electrostatic sampling device for point-of-care detection of bioaerosols2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Bioaerosols are not only a significant factor of air quality but contribute greatly to the spread of infectious diseases, specifically through expired pathogen-laden aerosols. Clear examples of airborne transmission include: the recent influenza pandemic of 2009, the ongoing tuberculosis epidemic, and yearly norovirus out- breaks, which affect millions of people worldwide and pose serious threats to public healthcare systems. Given these acute concerns and the critical lack of knowledge of the field, it is important to develop methods for sampling and detecting these air- borne pathogens. Specifically, detection at the point-of-care can play an important role in improving the outcome of patient care by providing rapid and convenient diagnostics.

    Electrostatic precipitation has emerged as a promising sampling tool for bio- aerosols, which together with a rapid analysis technique, can provide a powerful and integrated approach to pathogen detection or disease diagnosis at the point- of-care. Moreover, such a sampling-detection scheme could be a potentialy non- invasive breath sampling tool for diagnosis of respiratory infectious diseases.

    This thesis presents a sampling device based on electrostatic precipitation, for capture of bioaerosols, and designed for use at point-of-care settings. A multi-point- to-plane electrode configuration allows charging of aerosol particles and direct air- to-liquid capture within a miniaturized volume with potentential for concatenation with on-site detection methods. Performance of the device was evaluated, using non-biological aerosols, for geometric (inter-electrode distance), electrical (inter- electrode potential and corona current), and aerosol parameters (particle size and gas velocity). Moreover, four different collector designs were investigated for im- proved collection efficiency and other features suitable for point-of-care settings (e.g. easy sample extraction and minimized volume).

    The device was then validated, using bioaerosols, both in vitro and in vivo. In vitro validation was performed by capturing aerosolized influenza virus and analyz- ing the device collection efficiency. Lastly, prototype devices, designed for point- of-care, were validated in vivo with patients at the clinical setting. A pilot study was performed to capture exhaled pathogens from infected patients, with success- ful capture of exhaled bacteria.

  • 33.
    Ladhani, Laila
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Alsved, Malin
    Lund University.
    Löndahl, Jakob
    Lund University.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Efficient electrostatic sampling of aerosols into liquidManuscript (preprint) (Other academic)
    Abstract [en]

    Despite an increasing demand for the identification and quantification of airborne pathogens, there is an unmet need for point-of-care instruments that provide both capture and analysis of bioaerosols. The integration of electrostatic precipitation of aerosol particles directly into liquid with lab-on-a-chip-based biomolecular analysis has been previously suggested as a promising solution for this purpose.

    This work investigates liquid collector designs for such instruments. We hypothesize that the geometry of the collector; and the position of its air-liquid interface with respect to the electrostatic field and aerosol flow, can be optimized for a maximum sample concentration.

    We designed four liquid collectors with a small form factor, adapted for concatenating point-to-plane electrostatic precipitators with integrated downstream analysis. The collectors were evaluated for their absolute mass collection and their sample concentration, by sampling radioactive aerosol and color dye aerosol. 

    Collectors with their air-liquid surface parallel to the charged aerosol flow performed significantly better than those shaped as a cup with an air-liquid surface perpendicular to the flow. Whereas the electrostatic precipitators with the best performing collector designs captured only 32% of the aerosol mass compared to a commercial impinger, their resulting sample concentration was 4 times higher.    

  • 34.
    Ladhani, Laila
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Pardon, Gaspard
    Stanford University.
    Moons, Pieter
    University of Antwerp.
    Goossens, Herman
    University of Antwerp.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Sampling pathogens from breath using electrostatic and filter methods for diagnosis of lower respiratory tract infections– pilot study2018Report (Refereed)
    Abstract [en]

    A pilot study at a primary care center in Belgium sampled exhaled breath from patients presenting with flu-like symptoms. Electrostatic sampling methods revealed S. aureus, while filter sampling revealed virus. Additionally, for the first time, an electrostatic device was verified for exhaled breath at a clinical point-of-care setting.

  • 35. Larsson, S.
    et al.
    Johannisson, P.
    Kolev, D.
    Ohlsson, F.
    Nik, S.
    Liljeholm, Jessica
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ebefors, T.
    Rusu, C.
    Simple method for quality factor estimation in resonating MEMS structures2018In: Journal of Physics: Conference Series, Institute of Physics Publishing (IOPP), 2018, Vol. 1052, no 1, article id 012100Conference paper (Refereed)
    Abstract [en]

    The quality factor of a packaged MEMS resonating structure depends on both the packaging pressure and the structure's proximity to the walls. This type of mechanical constraints, which causes energy dissipation from the structure to the surrounding air, are applicable for oscillating energy harvesters and should be considered in the design process. However, the modelling of energy losses or the measurements of their direct influence inside a packaged chip is not trivial. In this paper, a simple experimental method to quantify the energy loss in an oscillating MEMS structures due to the surrounding air is described together with preliminary results. The main advantage of the method is the ability to characterize the damping contributions under different vacuum and packaging conditions without requiring any packaging of the harvester chip or fabrication of multiple devices with different cavity depths.

  • 36.
    Lenk, Gabriel
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Capillary driven devices for patient-centric diagnostics2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Lateral flow assays is an example of a successful microfluidic platform relying on passive fluid transport, making them suitable for patient-centric and point-of-care applications. Flow control and valving in capillary driven devices typically rely on design-imprinted functions and operations which can be a limiting factor. This thesis explores dissolvable polymer valves in capillary driven microfluidic systems, a novel type of valves with a timing function. The dissolvable valve technology was used to develop autonomous operations in lamination-based polymer microfluidic systems such as sequential reagent delivery, reagent release and volume-metering, and further utilizes this technology in the Dried Blood Spot (DBS) and Dried Plasma Spot applications described below. Lamination technology is suitable for the integration of the water-dissolvable polymer layers and allows upscaling at a relatively low cost. Advances in the development of LC-MS/MS systems enable the quantification of analytes in microliter-sized blood samples such as DBS. This makes DBS sampling a minimally invasive alternative to venous blood sampling with logistical and ethical advantages for users and health care providers. Unknown sample volume, spot inhomogeneity and hematocrit-related issues have been an obstacle for a wider acceptance of DBS sampling technology. To address these issues, a novel blood-sampling device, the microfluidic DBS card, has been developed within this thesis. The device function is based on capillary driven volume-metering and allows accurate and user independent collection of microliter-sized DBS, directly from a finger-prick. The microfluidic DBS card could help to eliminate some of the issues related to DBS sampling and contribute to a wider acceptance of the technology. Usability and reliability have been considered during the development to enable testing of the microfludic DBS card in a pre-clinical setting. For many analytes and biomarkers, conventional blood sample analysis is performed on plasma or serum samples. This thesis further discusses the use of capillary driven plasma separation based on commercially available asymmetric filtration membranes and capillary driven flow in microchannels. A novel concept for hematocrit and input-volume-independent collection of a 11.6~µl plasma sample from a single drop of blood is demonstrated. The plasma sample is automatically transferred to a sample collection pad forming a Dried Plasma Spot. This could be the next generation of dried sample matrix, enabling an accurate quantification of analytes in Dried Plasma Spots.

  • 37.
    Lenk, Gabriel
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ullah, Shahid
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Beck, Olof
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    A dried blood spot card for the collection of volumetric blood samples, quantification of caffeine in capillary blood from 44 volunteersManuscript (preprint) (Other academic)
  • 38.
    Lenk, Gabriel
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ullah, Shahid
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Beck, Olof
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    A dried blood spot card for the collection of volumetricblood samples, quantification of caffeine in capillary bloodfrom 44 volunteersManuscript (preprint) (Other academic)
  • 39.
    Lioubtchenko, Dmitri
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Smirnov, Serguei
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Anoshkin, Ilya V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Millimeter Wave Beam Steering Based on Optically Controlled Carbon Nanotube Layers2018In: 2018 43RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ), IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    In this paper, the dielectric constant changing of thin carbon nanotube layers under light illumination was used for phase shifter development in dielectric rod waveguides. This designed phase shifter was introduced to the dielectric rod waveguide dual-antenna array. The measurements of the beam steering at 90 GHz of the dielectric rod antenna array, covered with carbon nanotubes, were carried out.

  • 40. Lundin, Anders
    et al.
    Delsing, Louise
    Clausen, Maryam
    Ricchiuto, Piero
    Sanchez, Jose
    Sabirsh, Alan
    Ding, Mei
    Synnergren, Jane
    Zetterberg, Henrik
    Brolen, Gabriella
    Hicks, Ryan
    Herland, Anna
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. Karolinska Institutet, Sweden.
    Falk, Anna
    Human iPS-Derived Astroglia from a Stable Neural Precursor State Show Improved Functionality Compared with Conventional Astrocytic Models2018In: Stem Cell Reports, ISSN 2213-6711, Vol. 10, no 3, p. 1030-1045Article in journal (Refereed)
    Abstract [en]

    In vivo studies of human brain cellular function face challenging ethical and practical difficulties. Animal models are typically used but display distinct cellular differences. One specific example is astrocytes, recently recognized for contribution to neurological diseases and a link to the genetic risk factor apolipoprotein E (APOE). Current astrocytic in vitro models are questioned for lack of biological characterization. Here, we report human induced pluripotent stem cell (hiPSC)-derived astroglia (NES-Astro) developed under defined conditions through long-term neuroepithelial-like stem (ltNES) cells. We characterized NES-Astro and astrocytic models from primary sources, astrocytoma (CCF-STTG1), and hiPSCs through transcriptomics, proteomics, glutamate uptake, inflammatory competence, calcium signaling response, and APOE secretion. Finally, we assess modulation of astrocyte biology using APOE-annotated compounds, confirming hits of the cholesterol biosynthesis pathway in adult and hiPSC-derived astrocytes. Our data show large diversity among astrocytic models and emphasize a cellular context when studying astrocyte biology.

  • 41.
    Lyubchenko, Dmitri
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Smirnov, Serguei
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Anoshkin, Ilya V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Millimeter Wave Beam Steering Based on Optically Controlled Carbon Nanotube Layers2018Conference paper (Refereed)
    Abstract [en]

    In this paper, the dielectric constant changing of thin carbon nanotube layers under light illumination was used for phase shifter development in dielectric rod waveguides. This designed phase shifter was introduced to the dielectric rod waveguide dual-antenna array. The measurements of the beam steering at 90 GHz of the dielectric rod antenna array, covered with carbon nanotubes, were carried out.

  • 42. Lyubchenko, V. E.
    et al.
    Kalinin, V. I.
    Kotov, V. D.
    Lyubchenko, D. V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Radchenko, D. E.
    Telegin, S. A.
    Yunevich, E. O.
    Microstrip Antenna–Oscillators Integrated with a Waveguide Built in a Dielectric Substrate2018In: Journal of communications technology & electronics, ISSN 1064-2269, E-ISSN 1555-6557, Vol. 63, no 9, p. 1059-1063Article in journal (Refereed)
    Abstract [en]

    The design of a microwave oscillator based on a microstrip log-periodic antenna integrated with a field effect transistor and a waveguide built in a dielectric substrate has been developed and analyzed. The waveguide geometry provides the possibility of propagation and radiation at both the fundamental frequency of the log-periodic antenna and harmonics. Computer simulation of the oscillator design in a frequency range near resonance frequencies of the log-periodic antenna is conducted. The possibility of summation of powers of several antenna–oscillators arranged ias a linear phased array is investigated. 

  • 43.
    Maoz, Ben M.
    et al.
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA.;Tel Aviv Univ, Dept Biomed Engn, Fac Engn, Tel Aviv, Israel.;Tel Aviv Univ, Sagol Sch Neurosci, Tel Aviv, Israel.;Tel Aviv Univ, Ctr Nanosci & Nanotechnol, Tel Aviv, Israel..
    Herland, Anna
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA.;Karolinska Inst, Dept Neurosci, Swedish Med Nanosci Ctr, Stockholm, Sweden..
    FitzGerald, Edward A.
    Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Grevesse, Thomas
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Vidoudez, Charles
    Harvard Univ, Small Mol Mass Spectrometry Facil, Cambridge, MA 02138 USA..
    Pacheco, Alan R.
    Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA.;Boston Univ, Grad Program Bioinformat, Boston, MA 02215 USA.;Boston Univ, Biol Design Ctr, Boston, MA 02215 USA..
    Sheehy, Sean P.
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Park, Tae-Eun
    Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Dauth, Stephanie
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Mannix, Robert
    Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA.;Boston Childrens Hosp, Vasc Biol Program, Boston, MA 02115 USA.;Boston Childrens Hosp, Dept Surg, Boston, MA 02115 USA.;Harvard Med Sch, Boston, MA 02115 USA..
    Budnik, Nikita
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA..
    Shores, Kevin
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Cho, Alexander
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Nawroth, Janna C.
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    Segre, Daniel
    Boston Univ, Grad Program Bioinformat, Boston, MA 02215 USA.;Boston Univ, Biol Design Ctr, Boston, MA 02215 USA.;Boston Univ, Dept Phys, Dept Biomed Engn, Dept Biol, 590 Commonwealth Ave, Boston, MA 02215 USA..
    Budnik, Bogdan
    Harvard Univ, Mass Spectrometry & Prote Resource Lab, Cambridge, MA 02138 USA..
    Ingber, Donald E.
    Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA.;Boston Childrens Hosp, Vasc Biol Program, Boston, MA 02115 USA.;Boston Childrens Hosp, Dept Surg, Boston, MA 02115 USA.;Harvard Med Sch, Boston, MA 02115 USA.;Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Cambridge, MA 02138 USA..
    Parker, Kevin Kit
    Harvard Univ, Harvard John A Paulson Sch Engn & Appl Sci, Dis Biophys Grp, Cambridge, MA 02138 USA.;Harvard Univ, Wyss Inst Biol Inspired Engn, Boston, MA 02115 USA..
    A linked organ-on-chip model of the human neurovascular unit reveals the metabolic coupling of endothelial and neuronal cells2018In: Nature Biotechnology, ISSN 1087-0156, E-ISSN 1546-1696, Vol. 36, no 9, p. 865-+Article in journal (Refereed)
    Abstract [en]

    The neurovascular unit (NVU) regulates metabolic homeostasis as well as drug pharmacokinetics and pharmacodynamics in the central nervous system. Metabolic fluxes and conversions over the NVU rely on interactions between brain microvascular endothelium, perivascular pericytes, astrocytes and neurons, making it difficult to identify the contributions of each cell type. Here we model the human NVU using microfluidic organ chips, allowing analysis of the roles of individual cell types in NVU functions. Three coupled chips model influx across the blood-brain barrier (BBB), the brain parenchymal compartment and efflux across the BBB. We used this linked system to mimic the effect of intravascular administration of the psychoactive drug methamphetamine and to identify previously unknown metabolic coupling between the BBB and neurons. Thus, the NVU system offers an in vitro approach for probing transport, efficacy, mechanism of action and toxicity of neuroactive drugs.

  • 44.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    THz MEMS - Micromachining enabling new solutions at millimeter and submillimeter-wave frequencies (invited paper)2018In: Asia-Pacific Microwave Conference Proceedings, APMC, Institute of Electrical and Electronics Engineers Inc. , 2018, p. 81-84Conference paper (Refereed)
    Abstract [en]

    Since RF MEMS switches appeared more than 20 years ago, micromachining and micromechanics have been receiving large attention for enabling near-ideal microwave devices. MEMS switches and MEMS-switch based circuits have been through different development stages and are currently proving themselves commercially, among others for mobile-phone antenna-tuner switched-capacitor banks. However, micromachining can do much more than just two-dimensional MEMS switches for planar transmission-line technology: Three-dimensional, deep-silicon micromachining allows for new microwave devices with unprecedented performance, and has the potential to become an enabling technology for volume-manufacturable, reconfigurable submillimeter-wave and THz systems. This paper provides an overview of 3D silicon micromachining capability, and recent achievements of innovative microwave devices and systems enabled by micromachining high up into the THz spectrum are given, including the first MEMS-reconfigurable submillimeter-wave devices. Highlights of devices presented are a 3.3 bit MEMS phase shifter and a low-insertion loss / high-isolation MEMS waveguide switch operating at 500-750 GHz, and a micromachined technology for multi-pole, multi-transmission zero filers which enables multi-mode resonators with Q factors of 800 at 270 GHz. Furthermore, a technology is shown for very low loss micromachined waveguides with only 0.02 dB/mm loss at 200-300 GHz, which has enabled ultra-low loss waveguide components such as couplers and power combiners/splitters. 

  • 45.
    Quellmalz, Arne
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Smith, Anderson David
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Elgammal, Karim
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Fan, Xuge
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Delin, Anna
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Östling, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics, Integrated devices and circuits.
    Lemme, Max C.
    Chair of Electronic Devices, RWTH Aachen University.
    Gylfason, Kristinn
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Influence of Humidity on Contact Resistance in Graphene Devices2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 48, p. 41738-41746Article in journal (Refereed)
    Abstract [en]

    The electrical contact resistance at metal–graphene interfaces can significantly degrade the properties of graphene devices and is currently hindering the full exploitation of graphene’s potential. Therefore, the influence of environmental factors, such as humidity, on the metal–graphene contact resistance is of interest for all graphene devices that operate without hermetic packaging. We experimentally studied the influence of humidity on bottom-contacted chemical-vapor-deposited (CVD) graphene–gold contacts, by extracting the contact resistance from transmission line model (TLM) test structures. Our results indicate that the contact resistance is not significantly affected by changes in relative humidity (RH). This behavior is in contrast to the measured humidity sensitivity  of graphene’s sheet resistance. In addition, we employ density functional theory (DFT) simulations to support our experimental observations. Our DFT simulation results demonstrate that the electronic structure of the graphene sheet on top of silica is much more sensitive to adsorbed water molecules than the charge density at the interface between gold and graphene. Thus, we predict no degradation of device performance by alterations in contact resistance when such contacts are exposed to humidity. This knowledge underlines that bottom-contacting of graphene is a viable approach for a variety of graphene devices and the back end of the line integration on top of conventional integrated circuits.

  • 46.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    De Pietro, Luca
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gas diffusion and evaporation control using EWOD actuation of ionic liquid microdroplets for gas sensing applications2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 267, p. 647-654Article in journal (Refereed)
    Abstract [en]

    The lifetime of electrochemical gas sensors suffers from electrolyte evaporation and from the impracticality to perform recalibration. To tackle these issues, a prototype of a microfabricated gas diffusion controlling system, based on coplanar electrowetting-on-dielectric (EWOD) actuation of ionic liquid microdroplets, is presented. The system is designed to be integrated with electrochemical gas sensors to allow on-demand sealing of the sensing chamber from the environment. The MEMS device can be electrically toggled between an open and a closed state, in which the microdroplets are used to cover or uncover the openings of a perforated membrane connecting to the sensing compartment, respectively. This ON/OFF diffusion-blocking valve mechanism potentially allows for recalibration and for liquid electrolyte evaporation reduction when the sensor is not in use, thus extending the gas sensor lifetime. A one order of magnitude reduction of evaporation rate and a more than three orders of magnitude reduction of gas diffusion time were experimentally demonstrated. Ionic liquid movement can be performed with an applied AC voltage as low as 18 V, using super-hydrophobic cover plates to facilitate droplet motion. Furthermore, the shown ionic liquid micro-droplet manipulation provides a robust and low voltage platform for digital microfluidics, readily adaptable to serve different applications.

  • 47.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    De Pietro, Luca
    KTH.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Ionic liquid microdroplet manipulation by electrowetting-on-dielectric for on/off diffusion control2018In: 2018 IEEE Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1181-1184Conference paper (Refereed)
    Abstract [en]

    This article presents a proof-of-concept of a device able to control (ON/OFF) gas diffusion through a perforated membrane. The microfabricated system is based on electrowetting-on-dielectric (EWOD) actuation of ionic liquid (IL) microdroplets and can be electrically toggled from an open to a closed state, in which microdroplets cover or uncover the membrane openings, respectively. The system is designed to be integrated with liquid-electrolyte-based electrochemical gas sensors, to extend their lifetime by reducing electrolyte evaporation and allowing recalibration. The realized device was proven to limit gas diffusion and water evaporation through perforated portions of thin membranes on command.

  • 48.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    Microneedle-based system for minimally invasive continuous monitoring of glucose in the dermal interstitial fluid2018In: 2018 IEEE Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2018, Vol. 2018, p. 408-411Conference paper (Refereed)
    Abstract [en]

    We present a minimally invasive continuous glucose monitoring (CGM) device. The system consists in an ultra-miniaturized electrochemical sensor probe (70 × 700 × 50 μm3) inserted into the lumen of a hollow silicon microneedle. The implantable portion of the system is 50-fold smaller than state-of-the-art commercial products, thus enabling glucose monitoring in the dermis and a less invasive insertion procedure. Passive interstitial fluid extraction is achieved, making the daily use of this system practically viable. Moreover, the sensor positioning provides minimal delay in tracking glycaemia (5-10 minutes lag), due to the minimal distance between sensing electrodes and microneedle opening. The demonstrated system has therefore the potential to enable minimally invasive, fast and reliable CGM in patients affected by diabetes.

  • 49.
    Schröder, Stephan
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems. SenseAir AB.
    Towards Unconventional Applications of Wire Bonding2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents novel heterogeneous integration approaches of wire materials to fabricated and package MEMS devices by exploring unconventional applications of wire bonding technology. Wire bonding, traditionally endemic in the realm of device packaging to establish electrical die-to-package interconnections, is an attractive back-end technology, offering promising features, such as high throughput, flexibility and placement accuracy. Exploiting the advantages of state-of-the-art wire bonding technology and substitute the conventional micro welding approach with an innovative attachment concept, a generic integration platform for a multitude of wire materials is provided. This facilitates a cost-efficient and selective integration, which involves the attachment and shaping of a variety of intrinsically non-bondable wire materials. Furthermore, the selective integration of wire materials provides a simple method to generate complex suspended geometries, which circumvents the need for subsequent processing. The first part of this thesis reports of the integration of non-bondable shape memory alloy wires on wafer-level, which has led to an innovative method to fabricate micro actuators. Moreover, the integration of high performance resistive heating wires on chip-level is utilized to fabricate filament based infrared emitters, targeting non-dispersive infrared gas sensing of alcohol for automotive applications. In the second part, a series of unconventional applications of wire integration using the traditional thermo-sonic wire bonding approach is presented. A novel and low-cost nitric oxide gas sensor is realized by producing vertical bond wires featuring high aspect ratio. Next, the high placement accuracy of wire bonding tools is leveraged to integrate conductive metals cores for fabricating high aspect ratio through silicon vias. Finally, an advanced packaging approach for stress-sensitive MEMS gyroscopes is evaluated, which exclusively utilizes bond wires for realizing the die attachment.

  • 50.
    Shafagh, Reza Zandi
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Vastesson, Alexander
    KTH.
    Guo, Weijin
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Haraldsson, Klas Tommy
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    E-Beam Nanostructuring and Direct Click Biofunctionalization of Thiol–Ene Resist2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 10, p. 9940-9946Article in journal (Refereed)
    Abstract [en]

    Electron beam lithography (EBL) is of major importance for ultraminiaturized biohybrid system fabrication, as it allows combining biomolecular patterning and mechanical structure definition on the nanoscale. Existing methods are limited by multistep biomolecule immobilization procedures, harsh processing conditions that are harmful to sensitive biomolecules, or the structural properties of the resulting protein monolayers or hydrogel-based resists. This work introduces a thiol-ene EBL resist with chemically reactive thiol groups on its native surface that allow the direct and selective "click" immobilization of biomolecules under benign processing conditions. We constructed EBL structured features of size down to 20 nm, and direct functionalized the nanostructures with a sandwich of biotin and streptavidin. The facile combination of polymer nanostructuring with biomolecule immobilization enables mechanically robust biohybrid components of interest for nanoscale biomedical, electronic, photonic, and robotic applications.

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