Interplay between temperature effects and surface recombination process in UV photoresponse of ZnO nanowires

We demonstrate the interplay between surface recombination dynamics and environmental temperature in UV photoresponse of ZnO nanowire field effect transistors (FETs) with and without a passivation layer. We find that optoelectronic performance and photoresponse mechanism can be significantly altered by temperature, influencing surface chemical interaction and reaction associated with charge trapping. Particularly, regardless of surface passivation on nanowires, photocurrent gains and decay rate are drastically enhanced with increasing temperature. Furthermore, the temperature dependence of photoresponse behavior in nanowire FETs is discussed in terms of surface recombination rates, carrier concentration, surface potential barrier height, and charge trapping rates on the surface.