Improving the performance of a far-infrared quantum-ring-based photodetector utilizing asymmetric multi-barrier resonant tunneling

In this paper, a novel structure for quantum ring inter-subband photodetectors (QRIP) is proposed to reduce its dark current. Some additional layers including asymmetric multi-barrier resonant tunneling (AMBRT) in absorption region layers are exploited to provide near unity tunneling probability for generated photocurrents and completely reject thermally generated electrons. AMBRT structure consists of three asymmetric AlGaAs barriers and two InGaAs wells which are designed for operation wavelength of generated photocurrents by absorption of 20 μm. Simulation results show that AMBRT can considerably reduce the dark current compared to previously proposed resonant tunneling structure about three orders of magnitude. As a consequent, higher specific detectivity for AMBRT-QRIP is obtained in the order of ∼1011 cm Hz1/2/W at 100 K.