High responsivity quantum-dot infrared photodetector with Al0.1Ga0.9As blocking layers at both sides of the structure

Ten-stacked InAs/GaAs quantum-dot infrared photodetector with two Al0.1Ga0.9As blocking layers at both sides of the structure is investigated. High responsivity 1.73 A/W under low applied voltage of -1.4 V is observed at 20 K with peak wavelength ∼7.6 μm. The appearance of 3-6 μm photovoltaic response at higher temperature is attributed to the enhancement of E1-E2 and E2-tunneling transition with increasing temperature. Higher photocurrent avalanche process under negative bias is due to the front blocking layer barrier lowering which results from strain-induced dislocations.