Far-Infrared/THz Photodetector with Self-assembled Quantum Dots

In this paper, we report 21 mm photoresponse with InAs/InGaAs/GaAs quantum-dot-in-a-well photodetector structure. The self-assembled InAs quantum dots were grown on InGaAs/GaAs well structure via atomic layer molecular beam epitaxy and fabricated as intersubbamd photoconductive structure. The far-infrared/THz 21 mm photoresponse was measured at 4.2K. Photoresponses were observed over the range of λ = 3 μm to 25μm with peaks at 21, 15, 8 μm, respectively.