Comparison of InAs/GaAs Quantum Dot Infrared Photodetector and GaAs/(AlGa)As Superlattice Infrared Photodetector

A 10-stacked InAs/GaAs quantum dot infrared photodetector (QDIP) is compared with a 20-period GaAs/(AlGa)As superlattice infrared photodetector (SLIP). The 2–10 µm wide detection window and 187 mA/W high peak responsivity of InAs/GaAs QDIP at 7 µm at an applied voltage of 1.1 V are superior to the 7–10 µm detection window and 140 mA/W responsivity of GaAs/(AlGa)As SLIP at 9.4 µm at an applied voltage of 1.3 V. The photocurrent of SLIP is temperature-independent, whereas the photocurrent of QDIP increases with increasing temperature from 20 to 100 K. The polarization-dependent response ratios of 0.22 and 0.39 are observed for SLIP and QDIP, respectively.