Controllable photoresponse behavior in a single InAs nanowire phototransistor

Abstract

We demonstrate a single InAs nanowire phototransistor with controllable photoresponse behavior. The device is based on a top-gated nanowire field effect transistor with an electron mobility of 5790 cm2 V−1 s−1. In the absence of gate voltage, negative and positive photoresponses are observed under low and high illumination, respectively. By applying a relatively high negative/positive gate voltage, pure positive/negative photoresponse is obtained, respectively. The controllable photoresponse is attributed to a gate-voltage-induced barrier height modulation between the trap state energy level in the photogating layer and the conduction band of nanowire. The device is promising for optoelectronic applications.