Infrared detector based on interband transition of semiconductor quantum well within p-n junction

Abstract

Resonant excited carriers in quantum well will relax to the ground states and cannot escape from quantum wells to form photocurrent. However, it was recently observed that most of the photo-excited carriers in InGaAs/GaAs quantum wells within a p-n junction escape from quantum wells and form photocurrent rather than relax to the ground state of the quantum wells. The absorption coefficient of multiple quantum wells is also enhanced by a p-n junction. According to the phenomenon, a novel photon detector based on interband transition of strained InGaAs/GaAs quantum wells was fabricated. Without an anti-reflection layer, the external quantum efficiency up to 31% with only 100 nm absorption thickness was measured, corresponding an absorption coefficient of 3.7×10 4 cm -1 that is obviously higher than previously reported values. The room temperature detectivity of the device was 1.43×10 13 cm Hz 1/2 W -1 . For strained InAsSb/GaSb quantum wells material system, the detector showed a narrow response range from 2.1 μm to 3.0 μm with a peak around 2.6 μm at 200 K and a wide response range from 3.5 μm to 5.7 μm. The photon detectors based on interband transition show great potential applications in infrared detection operating at high temperature.