Proposal of a quantum ring intersubband photodetector integrated with avalanche multiplication region for high performance detection of far infrared

In this paper, a novel design of quantum ring infrared photodetector (QRIP) is proposed based on an additional avalanche multiplication region and its performance theoretically is investigated. The device consists of two intrinsic regions including: (i) quantum ring based absorption region which is responsible for absorption longer wavelength radiations and (ii) avalanche multiplication region for multiplying the generated carriers in absorption layer. Since lower electric fields are needed for absorption region to keep the dark current low and higher fields are required for multiplication region, a highly doped charge layer is used to separate absorption and multiplication regions and non-uniformly distribute the electric field. Also to further reduction of dark current, resonant tunneling barriers are embedded in absorption region to provide only a pass for optically excited electrons. Simulation results shows a higher responsivity and specific detectivity about 40 A/W and 2 × 1010 cm Hz1/2/W at λ = 20 μm, respectively.