Ultra-low-frequency self-oscillation of photocurrent in InxGa1−xAs∕Al0.15Ga0.85As multiple-quantum-well p–i–n diodes

We report an observation of ultra-low-frequency self-oscillation of photocurrent in InxGa1−xAs∕Al0.15Ga0.85As multiple-quantum-well p–i–n diodes. The photocurrent intensity shows self-oscillations with a characteristic frequency of ∼0.1Hz at low temperatures under reverse bias voltages. The photocurrent self-oscillation depends on applied bias voltage, temperature, illumination power, and indium content of quantum-well layers. These dependences indicate that the photocurrent self-oscillation is attributed to photogenerated carriers trapped in localized centers within InxGa1−xAs quantum-well regions.