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Ribet, F., De Pietro, L., Roxhed, N. & Stemme, G. (2018). Gas diffusion and evaporation control using EWOD actuation of ionic liquid microdroplets for gas sensing applications. Sensors and actuators. B, Chemical, 267, 647-654
Open this publication in new window or tab >>Gas diffusion and evaporation control using EWOD actuation of ionic liquid microdroplets for gas sensing applications
2018 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 267, p. 647-654Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Contact angle modulation, Electrochemical gas sensing, Electrowetting on dielectric, Gas diffusion valve, Ionic liquids, MEMS actuator
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-229250 (URN)10.1016/j.snb.2018.04.076 (DOI)000432775600076 ()2-s2.0-85046339371 (Scopus ID)
Funder
EU, European Research Council, 267528Swedish Research Council
Note

QC 20180601

Available from: 2018-06-01 Created: 2018-06-01 Last updated: 2018-08-20Bibliographically approved
Ribet, F., De Pietro, L., Roxhed, N. & Stemme, G. (2018). Ionic liquid microdroplet manipulation by electrowetting-on-dielectric for on/off diffusion control. In: 2018 IEEE Micro Electro Mechanical Systems (MEMS): . Paper presented at 31st IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2018, Belfast, United Kingdom, 21 January 2018 through 25 January 2018 (pp. 1181-1184). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Ionic liquid microdroplet manipulation by electrowetting-on-dielectric for on/off diffusion control
2018 (English)In: 2018 IEEE Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1181-1184Conference paper, Published 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.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Series
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), ISSN 1084-6999
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-228548 (URN)10.1109/MEMSYS.2018.8346773 (DOI)000434960900308 ()2-s2.0-85047004600 (Scopus ID)9781538647820 (ISBN)
Conference
31st IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2018, Belfast, United Kingdom, 21 January 2018 through 25 January 2018
Funder
EU, European Research CouncilSwedish Research Council
Note

QC 20180528

Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2018-09-05Bibliographically approved
Dubois, V. J., Raja, S. N., Gehring, P., Caneva, S., van der Zant, H. S. J., Niklaus, F. & Stemme, G. (2018). Massively parallel fabrication of crack-defined gold break junctions featuring sub-3 nm gaps for molecular devices. Nature Communications, 9, Article ID 3433.
Open this publication in new window or tab >>Massively parallel fabrication of crack-defined gold break junctions featuring sub-3 nm gaps for molecular devices
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2018 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, article id 3433Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-234594 (URN)10.1038/s41467-018-05785-2 (DOI)000442594800035 ()30143636 (PubMedID)2-s2.0-85052211020 (Scopus ID)
Note

QC 20180914

Available from: 2018-09-14 Created: 2018-09-14 Last updated: 2018-09-14Bibliographically approved
Ribet, F., Stemme, G. & Roxhed, N. (2018). Microneedle-based system for minimally invasive continuous monitoring of glucose in the dermal interstitial fluid. In: 2018 IEEE Micro Electro Mechanical Systems (MEMS): . Paper presented at 31st IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2018, Belfast, United Kingdom, 21 January 2018 through 25 January 2018 (pp. 408-411). Institute of Electrical and Electronics Engineers (IEEE), 2018
Open this publication in new window or tab >>Microneedle-based system for minimally invasive continuous monitoring of glucose in the dermal interstitial fluid
2018 (English)In: 2018 IEEE Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2018, Vol. 2018, p. 408-411Conference paper, Published 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.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Series
Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), ISSN 1084-6999
National Category
Embedded Systems
Identifiers
urn:nbn:se:kth:diva-228550 (URN)10.1109/MEMSYS.2018.8346574 (DOI)000434960900109 ()2-s2.0-85046998695 (Scopus ID)9781538647820 (ISBN)
Conference
31st IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2018, Belfast, United Kingdom, 21 January 2018 through 25 January 2018
Funder
VINNOVA, E!8573EU, European Research Council, 267528
Note

QC 20180528

Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2018-09-03Bibliographically approved
Errando-Herranz, C., Edinger, P., Colangelo, M., Björk, J., Ahmed, S., Stemme, G., . . . Gylfason, K. B. (2018). New dynamic silicon photonic components enabled by MEMS technology. In: Proceedings Volume 10537, Silicon Photonics XIII: . Paper presented at SPIE OPTO,2018 ,San Francisco, California, United States. SPIE - International Society for Optical Engineering, 10537
Open this publication in new window or tab >>New dynamic silicon photonic components enabled by MEMS technology
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2018 (English)In: Proceedings Volume 10537, Silicon Photonics XIII, SPIE - International Society for Optical Engineering, 2018, Vol. 10537Conference paper, Published 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.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2018
Keywords
MEMS, silicon photonics, tuning, ring resonator, waveguide dispersion, surface grating coupler
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-225106 (URN)10.1117/12.2297588 (DOI)
Conference
SPIE OPTO,2018 ,San Francisco, California, United States
Projects
VR-HETXMEMSM&M
Funder
Swedish Research Council, 621-2012-5364Swedish Research Council, B0460801EU, European Research Council, 277879EU, European Research Council, 267528
Note

QC 20180404

Available from: 2018-03-28 Created: 2018-03-28 Last updated: 2018-04-05Bibliographically approved
Laakso, M. J., Bleiker, S. J., Liljeholm, J., Mårtensson, G. E., Asiatici, M., Fischer, A. C., . . . Niklaus, F. (2018). Through-Glass Vias for Glass Interposers and MEMS Packaging Applications Fabricated Using Magnetic Assembly of Microscale Metal Wires. IEEE Access, 6, 44306-44317
Open this publication in new window or tab >>Through-Glass Vias for Glass Interposers and MEMS Packaging Applications Fabricated Using Magnetic Assembly of Microscale Metal Wires
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2018 (English)In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 44306-44317Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
Chip scale packaging, femtosecond laser, glass interposer, laser ablation, multichip modules, robotic assembly, self-assembly, spin-on glass, thermal expansion, through-glass via, through-silicon vias, TSV
National Category
Communication Systems
Identifiers
urn:nbn:se:kth:diva-235465 (URN)10.1109/ACCESS.2018.2861886 (DOI)000444505800001 ()2-s2.0-85050982480 (Scopus ID)
Funder
Knut and Alice Wallenberg FoundationVINNOVA, 324189Swedish Foundation for Strategic Research , GMT14-0071 RIF14-0017
Note

QC 20180928

Available from: 2018-09-28 Created: 2018-09-28 Last updated: 2018-10-02Bibliographically approved
Schröder, S., Gatty, H. K., Stemme, G., Roxhed, N. & Niklaus, F. (2017). A low-cost nitric oxide gas sensor based on bonded gold wires. In: TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems: . Paper presented at 19th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2017, Kaohsiung, Taiwan, 18 June 2017 through 22 June 2017 (pp. 1457-1460). Institute of Electrical and Electronics Engineers (IEEE), Article ID 7994334.
Open this publication in new window or tab >>A low-cost nitric oxide gas sensor based on bonded gold wires
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2017 (English)In: TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1457-1460, article id 7994334Conference paper, Published paper (Refereed)
Abstract [en]

In this paper we report of a novel and very simple fabrication method for realizing amperometric gas sensors using conventional wire bonding technology. Working and counter electrodes are made of 360 vertically standing bond wires, entirely manufactured by a fully automated, standard wire bonding tool. Our process enables standing bond wires with a length of 1.24 mm, resulting in an extremely high aspect-ratio of 50, thus effectively increasing the surface area of the working electrode. All gas sensor electrodes are embedded in a polymer-based, solid electrolyte. Therefore, laborious handling of liquid electrolytes can be avoided. Here, we report of a nitric oxide (NO) gas sensor that is capable of detecting NO gas concentrations down to the single-digit ppm range. The proposed approach demonstrates the feasibility towards a scalable and entire back-end fabrication concept for low-cost NO gas sensors.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-214452 (URN)10.1109/TRANSDUCERS.2017.7994334 (DOI)000426701400362 ()2-s2.0-85029388567 (Scopus ID)9781538627310 (ISBN)
Conference
19th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2017, Kaohsiung, Taiwan, 18 June 2017 through 22 June 2017
Note

QC 20171211

Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2018-03-22Bibliographically approved
Schröder, S., Rödjegård, H., Stemme, G. & Niklaus, F. (2017). A single wire large-area filament emitter for spectroscopic ethanol gas sensing fabricated using a wire bonding tool. In: TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems: . Paper presented at 19th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2017, Kaohsiung, Taiwan, 18 June 2017 through 22 June 2017 (pp. 315-318). IEEE, Article ID 7994052.
Open this publication in new window or tab >>A single wire large-area filament emitter for spectroscopic ethanol gas sensing fabricated using a wire bonding tool
2017 (English)In: TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems, IEEE, 2017, p. 315-318, article id 7994052Conference paper, Published paper (Refereed)
Abstract [en]

Non-dispersive infrared (NDIR) gas spectroscopy is a highly accurate optical gas sensing technology, which has been implemented in various industrial applications. However NDIR systems remain too expensive for many consumer and automotive apphcations. The cost of the infrared (IR) emitter component is a substantial part of the total system cost. In this paper we report of a single filament IR emitter that is fabricated using wire bonding technology. Our fabrication approach offers the prospect of a fully automated assembly by means of utihzing a wire bonding tool to integrate the single filament to the MEMS structured silicon substrate. An apphcation-specific wire bond trajectory enables the mechanical attachment of the filament to form the meander-shaped emitter with a total area of 1 mm2. The fabricated IR emitter utilizes a Kanthal (FeCrAl) filament with very high thermal stability and excellent emitting properties under atmospheric conditions. The packaged IR emitter has been characterized using Fourier transform infrared (FTIR) spectroscopy to study the emitted IR spectrum with respect to the requirements of NDIR systems.

Place, publisher, year, edition, pages
IEEE, 2017
Keywords
NDIR, non-dispersive infrared gas sensing, ethanol gas sensing, breath alcohol sensing, infrared emitter, wire bonding, non-bondable wire materials, integration platform, Kanthal filament
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-214450 (URN)10.1109/TRANSDUCERS.2017.7994052 (DOI)000426701400080 ()2-s2.0-85029362985 (Scopus ID)978-1-5386-2732-7 (ISBN)
Conference
19th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2017, Kaohsiung, Taiwan, 18 June 2017 through 22 June 2017
Funder
EU, European Research Council, 277879Swedish Research Council, 621-2011-4437VINNOVA, 2015-00402
Note

QC 20171211

Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2018-03-23Bibliographically approved
Dubois, V. J., Niklaus, F. & Stemme, G. (2017). Design and fabrication of crack-junctions. MICROSYSTEMS & NANOENGINEERING, 3, Article ID UNSP 17042.
Open this publication in new window or tab >>Design and fabrication of crack-junctions
2017 (English)In: MICROSYSTEMS & NANOENGINEERING, ISSN 2055-7434, Vol. 3, article id UNSP 17042Article in journal (Refereed) Published
Abstract [en]

Nanogap electrodes consist of pairs of electrically conducting tips that exhibit nanoscale gaps. They are building blocks for a variety of applications in quantum electronics, nanophotonics, plasmonics, nanopore sequencing, molecular electronics, and molecular sensing. Crack-junctions (CJs) constitute a new class of nanogap electrodes that are formed by controlled fracture of suspended bridge structures fabricated in an electrically conducting thin film under residual tensile stress. Key advantages of the CJ methodology over alternative technologies are that CJs can be fabricated with wafer-scale processes, and that the width of each individual nanogap can be precisely controlled in a range from <2 to >100 nm. While the realization of CJs has been demonstrated in initial experiments, the impact of the different design parameters on the resulting CJs has not yet been studied. Here we investigate the influence of design parameters such as the dimensions and shape of the notches, the length of the electrode-bridge and the design of the anchors, on the formation and propagation of cracks and on the resulting features of the CJs. We verify that the design criteria yields accurate prediction of crack formation in electrode-bridges featuring a beam width of 280 nm and beam lengths ranging from 1 to 1.8 mu m. We further present design as well as experimental guidelines for the fabrication of CJs and propose an approach to initiate crack formation after release etching of the suspended electrode-bridge, thereby enabling the realization of CJs with pristine electrode surfaces.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2017
Keywords
arrays, crack-junctions, lithography, nanofabrication, nanogap electrodes, notches, optimization, tunneling junctions
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-217431 (URN)10.1038/micronano.2017.42 (DOI)000414166400001 ()
Note

QC 20171117

Available from: 2017-11-17 Created: 2017-11-17 Last updated: 2018-05-22Bibliographically approved
Wang, X., Stemme, G. & Roxhed, N. (2017). High aspect ratio silicon field emitter arrays (FEAs) as miniaturized stable electron source for catheter-based radiotherapy. In: Proceedings of IEEE 30th International Conference on Micro Electro Mechanical Systems: . Paper presented at IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE conference proceedings
Open this publication in new window or tab >>High aspect ratio silicon field emitter arrays (FEAs) as miniaturized stable electron source for catheter-based radiotherapy
2017 (English)In: Proceedings of IEEE 30th International Conference on Micro Electro Mechanical Systems, IEEE conference proceedings, 2017Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a miniaturized electron source based on high aspect ratio silicon (Si) field emitter arrays (FEAs) intended for generating x-rays in a catheter-based radiotherapy application. The fabricated Si FEAs demonstrate stable emission currents of approximately 10 μA at an acceleration voltage of 21.7 kV for more than 15 minutes under moderate vacuum requirements. The current stability was enhanced by the introduction of a field compensation frame design for the electric field distribution and a tip conditioning procedure of the Si FEAs. The experimental results are in line with the requirement of delivering relevant doses for cancer radiotherapy. 

Place, publisher, year, edition, pages
IEEE conference proceedings, 2017
Keywords
silicon, field emission, field emitter arrays (FEAs), miniaturized, electron source, x-ray, radiotherapy, brachytherapy, catheter-based, minimally invasive
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-199869 (URN)000402552000135 ()2-s2.0-85015783123 (Scopus ID)
Conference
IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS)
Projects
X-Ray
Note

When citing this work, please cite the original published paper.

QCR 20170206

QC 20170607

Available from: 2017-01-17 Created: 2017-01-16 Last updated: 2017-07-03Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9552-4234

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