Large enhancement in photon detection sensitivity via Schottky-gated CdS nanowire nanosensors

Abstract

The Schottky contact based photon detection was demonstrated using CdS (visible light responsive), silicon (indirect n-type oxygen-non-adsorbing), and CuO (indirect p-type oxygen-adsorbing) nanowire nanosensors. With changing one of the two nanowire-electrode contacts from ohmic to Schottky, detection sensitivities as high as 105% were achieved by the CdS nanowire nanosensor operated at the reverse bias mode of −8 V, which was 58 times higher than that of the corresponding ohmic contact device. The reset time was also significantly reduced. In addition, originally light nonresponsive silicon and CuO nanowires became light responsive when fabricated as a Schottky contact device. These improvements in photon detection can be attributed to the Schottky gating effect realized in the present nanosensor system by introducing a Schottky contact.