Mobility enhancement in electric double layer gated n-ZnO ultraviolet photodetector by synergy of gate and illumination: A photo Hall study

Abstract

We report a large enhancement of the Hall mobility of a ZnO film (channel) by simultaneously application of an ultraviolet illumination along with a gate bias in an electric double layer field effect transistor configuration. The effect arises from a synergy between the illumination and the field effect (FE), leading to large enhancement of the channel conductivity and the photo response. We propose that large carrier density created by the simultaneous presence of the illumination and the FE leads to neutralization of some of the oxygen charged vacancies which in turn reduce potential scattering leading to the enhanced mobility.