High gain GaN/AlGaN heterojunction phototransistor

Abstract

A GaN/AlGaN heterojunction bipolar phototransistor with gain in excess of 105 was demonstrated. From 360 to 400 nm, an eight orders of magnitude drop in responsivity was achieved. The phototransistor features a rapid electrical quenching of persistent photoconductivity, and exhibits high dark impedance and no dc drift. By changing the frequency of the quenching cycles, the detection speed of the phototransistor can be adjusted to accommodate specific applications. These results represent an internal gain UV detector with significantly improved performance over GaN-based photoconductors.