Ultrahigh-sensitive AlGaAs-GaAs punchthrough heterojunction phototransistor

An avalanche enhanced AlGaAs-GaAs punchthrough heterojunction phototransistor with an improved guard-ring emitter structure has been proposed. It has demonstrated a record high sensitivity of 5790 A/W and optical conversion gain of 10810 at 400-nW incident optical power level. Its novel guard-ring emitter structure can suppress peripheral recombination current more effectively, provide capability to enhance and tune the optical conversion gain at low-incident optical power and reduce the effective emitter area.