A new functional optical-electrical switch using a multi-emitter heterojunction phototransistor

We propose a new functional optical-electrical switching device: a multi-emitter heterojunction photo-transistor (ME-HPT) using a multi-emitter heterojunction bipolar transistor (ME-HBT) structure. In this device, the collector current (I/sub C/) can be controlled by not only the incident radiant power (P/sub 0/) but also the voltage difference between emitters (V/sub EE/). We fabricated ME-HPT's using InGaAs/InP heterostructures and confirmed the normal operation. Using only one ME-HPT, we have successfully demonstrated a new functional optical-electrical switching operation, which can switch on only when both the electrical and optical signals are high.<
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