Gas Sensing Approaches Based on WO3 Nanowire-Back Gated Devices

Abstract

This paper present a new design and configuration of metal oxide gas sensor based on back-gated device that can operate at low temperature. Gold electrodes patterned onto an oxidized, heavily doped, p-type silicon substrate were designed and fabricated at a wafer level. The Au—electrodes were used as source—drain metal contacts and a third gate electrode was connected from the backside of the substrate. Tungsten oxide nanowires decorated with Pt-nanoparticles were directly grown employing aerosol assisted-CVD (AA-CVD) on top of the electrode area. Gas sensing properties of the back-gated device in the presence of air and hydrogen gas reveals characteristic response modulated by the applied gate potential at room temperature. It was found that the IDS-VGS plot illustrates characteristic field effect transistor with an inherent adsorptive surface electron transfer of the nanowires accompanied with the applied gate potential induced charge transfer. These counter-acting mechanisms might persuade for the application of back-gated device as a promising n-channel metal oxide gas sensor operating at low temperature or even room temperature.

Keywords

• WO3 nanowire
• FET
• AA-CVD
• gas sensor