Impact ionization in narrow band gap CdHgTe quantum well with "resonant" band structure

TL;DR

This paper investigates impact ionization in a narrow band gap CdHgTe quantum well with a resonant band structure, showing a significant increase in ionization probability due to the unique subband energy configuration.

Contribution

It introduces a detailed calculation of impact ionization probabilities in a specific quantum well structure with near-resonant subband energies, highlighting the enhanced ionization effects.

Findings

Impact ionization probability increases by about two orders of magnitude in the second subband.

Small momentum transfer impact ionization is enabled by the resonant band structure.

Experimental detection methods for impact ionization are discussed.

Abstract

Impact ionization probabilities were calculated in a CdHgTe quantum well, where the distance between electron subbands is close to the band gap energy. This band structure enables impact ionization with small momentum transfer for electrons in the second subband. The study demonstrates that such processes increase the impact ionization probability by approximately two orders of magnitude compared to the impact ionization probability for electrons in the first subband, for which transitions with small momentum changes are impossible. The probability of single impact ionization during the electron energy loss due to optical phonon emission is estimated. Experimental methods for detecting impact ionization in this structure are discussed.