Paper
7 October 1994 Wave packet simulations of escape and capture probabilities in multiquantum-well infrared detectors
Abraham Fraenkel, Yoram Betser, Elieser Finkman, Gad Bahir
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Abstract
There are several responsivity and gain models adequate to MQW detectors. All are related to two fundamental properties: the escape efficiency of a photo-excited carrier out of the well boundary (Pout) and the capture (or crossing) probability (Pc or Pw equals 1-Pc). In this work we present a rigorous calculation of the escape and capture probabilities based on a Quantum Mechanical approach. In this vicinity of the well the electrons are treated as Gaussian Wave-Packets. The simulation calculates the quantum mechanical reflections encountered by the packets at the interfaces as a function of kinetic energy and applied electric field. The relaxation processes into the bound sub-level are taken into account by introducing an imaginary potential. The simulations are carried out on both stepped and rectangular structures. The step reduces the dwell time above the well and hence the capture probability. This result is in good qualitative agreement with responsivity measurements on such structures. The effects of interface charge and non-uniform charge distribution are also considered. We assume an accumulation of negative sheet charge on the `inverted' interface facing the substrate. This excess charge, introduced during the growth sequence, induces structural asymmetry. The modified well potential is calculated self-consistently and results in an increased barrier height for carriers propagating towards the substrate. Those results are consistent with the asymmetrical responsivity and noise characteristics measured by various groups.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Abraham Fraenkel, Yoram Betser, Elieser Finkman, and Gad Bahir "Wave packet simulations of escape and capture probabilities in multiquantum-well infrared detectors", Proc. SPIE 2274, Infrared Detectors: State of the Art II, (7 October 1994); https://doi.org/10.1117/12.189242
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KEYWORDS
Interfaces

Electrons

Sensors

Quantum efficiency

Infrared detectors

Reflection

Monte Carlo methods

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