Gate voltage tuning of photo-responses in n-AlGaAs/GaAs/AlGaAs double-heterojunction

We demonstrate that the gate voltage Vg tunes the Schottky photocurrent ISG for the irradiation of two lights (Light A and B) in an n-AlGaAs/GaAs/AlGaAs double-heterojunction. Light A is a 975-nm laser that illuminates the entire Schottky gate region at 280 μW/mm2. Light B is a 670-nm laser that locally illuminates the ungated region at 0.4 μW. When Vg = 0 V, Light B doubles ISG for Light A. At Vg = 87 mV, ISG is generated only when both Light A and B are irradiated simultaneously, like the logical operation A∩B. When Vg = 165 mV, ISG is induced only for the illumination of Light A alone, like A∩B̄.