HIGH-GAIN GAN ALGAN HETEROJUNCTION PHOTOTRANSISTOR/

GaN/A1GaN heterojunction bipolar phototransistor with gain in excess o f 10(5) was demonstrated. From 360 to 400 nm, an eight orders of magni tude drop in responsivity was achieved. The phototransistor features a rapid electrical quenching of persistent photoconductivity, and exhib its high dark impedance and no de drift. By changing the frequency of the quenching cycles, the detection speed of the phototransistor can b e adjusted to accommodate specific applications. These results represe nt an internal gain UV detector with significantly improved performanc e over GaN-based photoconductors. (C) 1998 American Institute of Physi cs.