Avalanche quantum dot-in-well long wavelength infrared photodetectors: Linear and Geiger mode operation

•A quantum dot-in-well based avalanche photodetector is presented and studied.•The operating wavelength can be tuned by design of well thickness and composition.•Resonant tunneling barriers are included to reduce the dark current.•Linear and Geiger mode operation of this detector is investigated.•About one order of magnitude improvement in responsivity and detectivity achieved.

Employment of additional multiplication region in the structure of quantum dots-in-well (DWELL) intersubband photodetectors can be a useful alternative for amplification of the photocurrent and giving higher gain to detected optical signal. For such detector the photocurrent of DWELL detector is increased by avalanche multiplication to achieve higher responsivity and resonant tunneling barriers are used in absorption region to reduce the dark current. In this paper the linear and Geiger mode operation of proposed detector is studied for operation at λ = 11 μm. In linear operation, the specific detectivity (D*) is increased about one order of magnitude in comparison to experimentally reported conventional DWELL detectors. We also report the single photon detection around mid and long infrared wavelength by gated mode operation of this detector with single photon quantum efficiency of about 3%.