Contact Properties and Surface Reaction Kinetics of Single ZnO Nanowire Devices Fabricated by Dielectrophoresis

Pau, J.L., Garcia Nunez, C. , García Marín, A., Guerrero, C., Rodríguez, P., Borromeo, S. and Piqueras, J. (2014) Contact Properties and Surface Reaction Kinetics of Single ZnO Nanowire Devices Fabricated by Dielectrophoresis. In: Oxide-based Materials and Devices V, San Francisco, CA, USA, 02-05 Feb 2014, 89871Q. ISBN 9780819499004 (doi: 10.1117/12.2044456)

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Abstract

This work describes the development of ZnO nanowire (NW) devices for ultraviolet detection and cost-effective gas sensing. A dielectrophoresis (DEP) flow cell fabricated for the integration of NWs on different substrates is presented. The system includes the possibility to set characteristic parameters such as alternating current (AC) frequency, amplitude or flow speed in order to control NW trapping on specific sites defined by micro-gapped electrodes. The electrical characteristics of the rectifying metal/NW contact fabricated by DEP are investigated in darkness and under direct illumination of the metal-NW interface through the ZnO NW. A significant downshift of the turn-on voltage is observed in the current-voltage characteristics during the illumination with photon energies higher than the ZnO bandgap. The reduction is attributed to a barrier height lowering induced by interface charge emission. The effects of AC bias on the thermal drift of the DC average current in NW devices are also discussed. Finally, the reaction kinetics of ethanol and water vapors on the NW surface are compared through the analysis of the DC current under direct exposure to gas flows. Device responses to more complex compound mixtures such as coffee or mint are also monitored over time, showing different performance in both cases.

Item Type:Conference Proceedings
Additional Information:Proceedings of SPIE, Volume 8987
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Garcia Nunez, Dr Carlos
Authors: Pau, J.L., Garcia Nunez, C., García Marín, A., Guerrero, C., Rodríguez, P., Borromeo, S., and Piqueras, J.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
ISBN:9780819499004

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