Change search
Refine search result
1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Araujo, C. Moysés
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Kapilashrami, Mukes
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Jun, Xu
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Jayakumar, Onattu D.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Nagar, Sandeep
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Wu, Yan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Århammar, Cecilia
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Gehring, Gillian A.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Room temperature ferromagnetism in pristine MgO thin films2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, no 23Article in journal (Refereed)
    Abstract [en]

    Robust ferromagnetic ordering at, and well above room temperature is observed in pure transparent MgO thin films (<170 nm thick) deposited by three different techniques. Careful study of the wide scan x-ray photoelectron spectroscopy rule out the possible presence of any magnetic contaminants. In the magnetron sputtered films, we observe magnetic phase transitions as a function of film thickness. The maximum saturation magnetization of 5.7 emu/cm(3) is measured on a 170 nm thick film. The films above 500 nm are found to be diamagnetic. Ab initio calculations suggest that the ferromagnetism is mediated by cation vacancies.

  • 2. Moysés Araújo, C.
    et al.
    Kapilashrami, Mukes
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jun, Xu
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Jayakumar, Onattu D.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Nagar, Sandeep
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Wu, Yan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Århammar, Cecilia
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics.
    Rao, K Venkat.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Unusual ferromagnetism above room temperature in undoped thin films and nanoparticles of MgOManuscript (Other academic)
  • 3.
    Wu, Yan
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Functional Metal Oxide Materials Deposited by Inkjet Printing Technique2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents a comprehensive study of the intrinsic room temperature ferromagnetism in 85 to 100nm thin films produced by in situ deposition of industrially important pristine MgO and ZnO by inkjet printing. It is suggested that the observed long range magnetic order, the so-called do magnetism in these oxides arises from cation vacancies. Wide range scanned XPS studies rule out any other source but of intrinsic nature in this first report on inkjetted oxide films. (Accepted for publication in APL 2010; and JPC Letters 2010)

    The functional properties of the above oxide films have been exploited by inkjet patterning devices based on UV-sensing, photoconductivity and field-effect transistors with attractive features. Development of devices and prototypes is an area of growing importance among future technologies. Complementary to photolithography, inkjet printing is increasingly considered a cost-effective and flexible microfabrication method to structure functional materials. The ease of mass fabrication and the inherent flexibility of inkjet technology make it a suitable method for the manufacture of microsystems and components. The results presented in this dissertation summarize recent achievements in this relatively new technology for the development of miniaturized devices:

    1)      RTFM in pure and Mn-doped ZnO thin films: (IEEE Trans. Magnetics 2010) Tailored RTFM in Mn-doped ZnO thin films synthesized by inkjet printing has been realized. Highly c-axis oriented 80 to 400 nm thin films are obtained with a magnetic moment as large as 2.1 μB/Mn2+. X-ray absorption and emission spectra measurements at the O K edge and the Mn L edge suggest strong p-d hybridization between the Mn2+ and O2-. Furthermore, Mn L edge XAS indicates the emergence of Mn3+/Mn4+ mixed valence states for films annealed above 500 °C that leads to suppression of ferromagnetic ordering.

    2)      RTFM in MgO thin films (JPC Letters 2010) Solution processed homogeneous (200) oriented MgO ~85 nm thin films show room temperature ferromagnetism with a saturation magnetization MS as high as ~0.63 emu/g. X-ray photoelectron spectroscopy investigations show the absence of any contamination while the Mg 2p, and O 1s spectra indicate the role of defect structure at the Mg site. By controlling the pH values of the precursors the concentration of the defects can be varied and hence to tune the magnetization.

    3)      Photoconductivity of pure and Al-doped ZnO thin films: (2009 MRS proceedings). Pure and Al-doped ZnO, 120-300 nm thin films are found to exhibit a transmittance above 85-90% in the visible wavelength range. The electrical conductivity of Al-doped ZnO thin films is found to be larger by two orders of magnitude than that for pure ZnO films while the photoconductivity is found to increase by about three orders of magnitude under UV irradiation.

    4)      The photosensitivity of CaS-composited ZnO thin films: (JPC Letters 2010) We have engineered a 3 orders of magnitude enhancement of the ultraviolet photoresponse of ZnO thin films, fabricated by inkjet printing, and then capped with CdS nanoparticles by dip coating. As a consequence, the decay time of the photoresponse is reduced to about 4 ms. Capping with CdS not only suppresses the detrimental passivation layer of ZnO thin films, but also generates an interfacial carrier transport layer to reduce the probability of carrier recombination.

    5)      Indium-doped Zinc oxide field effect transistors: (Materials Letters 2010) In darkness the In-doped zinc oxide field effect transistor (IZO-FET) exhibits a saturation current level of about 10 μA, an incremental mobility as high as 8 cm2 V-1 s-1, and a current on/off ratio of 104 ~105. When illuminated by 363 nm, 1.7 mW/cm2 UV light, the IZO-FET displays a photocurrent of 2 mA, and a darkness current of ~20 nA at an optimized gate voltage of -2V. The device is effectively turned on in about 5 ms and off in 10 ms.

    

  • 4.
    Wu, Yan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Girgis, Emad
    Ström, Valter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Voit, Wolfgang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Rao, K. V.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Ultraviolet light sensitive In-doped ZnO thin film field effect transistor printed by inkjet technique2011In: Physica Status Solidi (A) Applications and Materials, ISSN 1862-6300, Vol. 208, no 1, p. 206-209Article in journal (Refereed)
    Abstract [en]

    This indium-doped zinc oxide field effect transistor (IZO-FET) with a large ultraviolet (UV) detection sensitivity has been fabricated by inkjet printing technique. In darkness, the IZO-FETs exhibit a saturation current level of about 10 mu A, an incremental mobility as high as 8 cm(2) V-1 s(-1), and a current on/off ratio of 10(4)-10(5). When illuminated by 363 nm, 1.7 mW cm(-2) UV light, the IZO-FET displays a photocurrent of 2 mA, and a darkness current of similar to 20 nA at an optimized gate voltage of -2 V. The device is effectively turned on in about 5 ms and off in 10 ms. These results suggest that the IZO-FET fabricated by inkjet printing could be a low cost highly sensitive UV photodetector.

  • 5.
    Wu, Yan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Voit, Wolfgang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Tamaki, Takahiko
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Jayakumar, O. D.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Liu, Y. S.
    Glans, P. A.
    Chang, C. L.
    Guo, Jin Hua
    Room Temperature Ferromagnetism and Fast Ultraviolet Photoresponse of Inkjet-Printed Mn-Doped ZnO Thin Films2010In: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 46, no 6, p. 2152-2155Article in journal (Refereed)
    Abstract [en]

    We have synthesized Mn-doped ZnO thin films by inkjet printing using a two-step annealing process at 200 C for the decomposition of the organic compounds, and at various temperatures above 400 degrees C to tailor room temperature ferromagnetism. Highly c axis oriented 80 to 400 nm thin films on ( 001) Si substrates are obtained with a magnetic moment as large as 2.1 mu(B)/Mn2+. X-ray absorption and emission spectra measurements at the O K edge and the Mn L edge suggest strong p-d hybridization between the Mn2+ and O2-. Furthermore, Mn L edge XAS indicates the emergence of Mn3+ /Mn4+ mixed valence states for films annealed above 500 degrees C that leads to suppression of ferromagnetic ordering. All of these films show large and fast ultraviolet (UV) photoresponse with the decay times of about 0.5 ms, suggesting the potential for designing multifunctional UV sensors.

  • 6.
    Wu, Yan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Tamaki, Takahiko
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Riazanova, Anastasia
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Enhanced photoresponse of inkjet printed ZnO thin films induced by chemically capped CdS nanoparticles by dip coating2009In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 7402, no 740207Article in journal (Refereed)
    Abstract [en]

    Monodispersed CdS nanoparticles (NP) are dip coated on porous ZnO thin film deposited by inkjet printing. Optical absorption characteristics of the composite films show that the composite exhibits two main peaks centered at 355 nm due to the absorption at UV region from ZnO, and 433 nm arising from CdS NP. On UV radiations the electrical conductivity of CdS/ZnO composite thin film with 5 dip cycles is found to be enhanced more than three orders magnitude compared with that of the ZnO which we attribute to be the effect of interfacial charge transfer. Also, the UV photoresponse of ZnO shows pronounced enhancement after CdS capping. 

  • 7.
    Wu, Yan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Tamaki, Takahiko
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Volotinen, Tarja
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Enhanced Photoresponse of Inkjet-Printed ZnO Thin Films Capped with CdS Nanoparticles2010In: J PHYS CHEM LETT, ISSN 1948-7185, Vol. 1, no 1, p. 89-92Article in journal (Refereed)
    Abstract [en]

    Composite semiconductors provide routes for realizing high-performance electronic devices, but for many applications of such devices, low-cost manufacturing techniques are desirable. We have engineered a 3 orders of magnitude enhancement of the ultraviolet photoresponse of ZnO thin films, fabricated "in situ" by drop-on-demand inkjet printing, and then capped with CdS nanoparticles by dip. coating. As a consequence, the decay time of the photoresponse is. reduced to about 4 ms. Thus, capping with CdS not only suppresses the detrimental passivation layer of ZnO thin films, but also generates an interfacial carrier transport layer to reduce the probability of carrier recombination.

  • 8.
    Wu, Yan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Tamaki, Takahiro
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Voit, Wolfgang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Ultraviolet photoconductivity of pure and Al doped ZnO thin films by inkjet printing2009In: NOVEL MATERIALS AND DEVICES FOR SPINTRONICS / [ed] Sanvito S, Heinonen O, Dediu VA, Rizzo N, Warrendale, PA: MATERIALS RESEARCH SOCIETY , 2009, Vol. 1183, p. 133-138Conference paper (Refereed)
    Abstract [en]

    Pure ZnO, and Al doped ZnO, 120-300 nm thin films on glass substrates, were synthesized by inkjet printing technique using zinc and aluminum acetate solution as precursors and a two stage heat treatment process to obtain polycrystalline hexagonal wurtzite structure with the mean grain size of 25 and 30 nm respectively. All films exhibit a transmittance above 85-90% in the visible wavelength range below 700 nm. In the Al doped films the UV absorption spectra show a strong absorption onset below 380nm followed by shoulders centered around 325 nm depending on the film thickness. The electrical conductivity of Al doped ZnO thin films is larger by two orders of magnitude than that for pure ZnO films while the photoconductivity increases by about three orders of magnitude under UV irradiation. The photoresponse of the films with UV irradiation in terms of the rise and decay times in the frequency range from 5 to 500 Hz is also presented and discussed.

  • 9.
    Wu, Yan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics. Faculty of Materials Sci. and Chemical Eng., China Univ. of Geosciences, Wuhan, China .
    Zhan, Y.
    Fahlman, M.
    Fang, Mei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    'In-situ' solution processed room temperature ferromagnetic MgO thin films printed by inkjet technique2011In: Materials Research Society Symposium Proceedings, 2011, p. 105-109Conference paper (Refereed)
    Abstract [en]

    We report on 'in-situ' solution processed homogeneous (200) oriented MgO ∼85nm thin films deposited on Si substrates by inkjet printing. These films are found to show ferromagnetic order beyond room temperature with a saturation magnetization MS as high as ∼0.63 emu/g. X-ray photoelectron spectroscopy investigations show the absence of any possible contamination effects, while the Mg 2p, and O 1s spectra indicate that the role of defect structure at the Mg site is important in the observed magnetism. By controlling the pH values of the precursors the concentration of the defects can be varied and hence tune the magnetization at room temperature. The origin of magnetism in these MgO thin films appears to arise from the cation vacancies.

  • 10.
    Wu, Yan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Zhan, Yiqiang
    Fahlman, Mats
    Rao, K. Venkat
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    Belova, Lyubov
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Engineering Material Physics.
    'In-situ' Solution Processed Room Temperature Ferromagnetic MgO Thin Films Printed by Inkjet TechniqueIn: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185Article in journal (Other academic)
1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf