Description of transport mechanisms in a very long wave infrared quantum cascade detector under strong magnetic field

Abstract

Measurements of current have been performed on a very long wave infrared quantum cascade detector under strong magnetic field applied parallel to the growth axis, both under dark and light conditions. The analysis of dark current as a function of temperature highlights three regimes of transport involving the different energy levels of the structure. For photocurrent analysis, we developed a model based on a rate equation approach taking into account all the electronic levels of the structure. This model is in agreement with the oscillatory component of the experimental magnetophotocurrent. It allows to identify the key points controlling the electronic transport such as extraction from the upper level of the optically active quantum well, location of ionized impurities and scattering mechanisms involved in the structure. This work is valuable for the future conception of highperformance quantum cascade detectors in infrared and far infrared range.

Broadband Response and a Transformation between Dual‐ and Single‐Wavelength Detection in Coupled Doped‐Well Quantum Cascade Detector

“…Quantum cascade detector (QCD), as a photovoltaic device, has made itself one of the prevalent devices in infrared detection. [1][2][3][4][5] Similar to self-powered photodetectors, [6][7][8] the QCD device could operate at zero bias, resulting in low dark current and high signal-to-noise ratio (S/N). [9,10] The difference is that the QCD is an intersubband (ISB) transition device and thus has a faster response time (≈1 ps), although at the cost of quantum efficiency.…”

“…Energy levels interaction in the cascade structure is closely related to the performance of the detector, involving the photo electric conversion efficiency, [16,17] electrons migration behavior, [2,7] and dark current, [18,19] etc. For instance, a higher responsivity has been exhibited via adjusting the overlap integral (OI) between the upper energy level and extractor energy level.…”