High-speed Ga 0.51 In 0.49 P/GaAsheterojunction phototransistors

A high speed Ga0.51In0.49P/GaAs heterojunction phototransistor grown by metal organic vapour phase epitaxy (MOVPE) is reported. High frequency measurements indicate that the device has a cutoff frequency of 1.7 GHz with a 50 Ω output load. The impulse response of the device is measured to be ~60 ps full width at half maximum (FWHM). The phototransistor exhibits an external AC gain of 29 at an incident power of 500 µW.