High-Temperature Operation GaSb/GaAs Quantum-Dot Infrared Photodetectors

A ten-period GaSb/GaAs quantum-dot infrared photodetector (QDIP) is investigated in this letter. A broad detection window 2-5 μm with peak responses at ~ 3.7 μm is observed. Compared with the 4- to 8-μm detection window of a standard InAs/GaAs QDIP, the detection wavelengths of the GaSb/GaAs QDIP are shifted to the 2- to 5- μm range such that water absorption is avoided. The enhanced normal incident absorption of the GaSb QDIP is attributed to its smaller sizes compared with InAs QDs. Without additional high-bandgap barrier layers, the 200 K spectral response of the simple stacked GaSb/GaAs QDIP has already been observed, which has demonstrated the potential for practical applications of the GaSb/GaAs QDIPs.