Quantum scattering engineering for the reduction of dark current in very long wavelength quantum well infrared photodetector

TL;DR

This paper demonstrates that shifting dopant impurity layers away from the center of quantum wells significantly reduces dark current in long-wavelength quantum well infrared photodetectors at low temperatures, enhancing their sensitivity.

Contribution

It introduces a novel approach of dopant layer positioning to suppress impurity scattering, validated by experiments and theory, improving detector performance.

Findings

Dark current is significantly reduced by dopant layer shifting.

Interwell tunneling dominated by charged impurity scattering.

Experimental results align with theoretical predictions.

Abstract

Dark current is shown to be significantly reduced in quantum well infrared photodetectors in the tunneling regime, i.e. at very low temperature, by shifting the dopant impurity layers away from the central part of the wells. This result confirms that the interwell tunneling current is dominated by charged impurity scattering in usual structures. The experimental results are in good quantitative agreement with the proposed theory. This dark current reduction is pushing further the ultimate performances of quantum well infrared photodetectors for the detection of low infrared photon fluxes. Routes to further improvements are briefly sketched.