GaAlAs/GaAs heterojunction bipolar phototransistors grown by LPE with a current gain of 50 000

Abstract

A simple mesa GaAlAs/GaAs heterojunction bipolar phototransistor fabricated by LPE growth technique is presented. A high current gain of the order of 50 000 has been obtained and is believed to be the highest ever reported for a bipolar device. The corresponding high sensitivity is about 15 000 A/W for an 800 nm illumination wavelength.