Defect capturing and charging dynamics and their effects on magneto-transport of electrons in quantum wells

TL;DR

This paper investigates how defect capture, charging, and defect-related dynamics influence the magneto-transport properties of electrons in quantum wells, providing comprehensive analytical and self-consistent models.

Contribution

It introduces a detailed theoretical framework combining defect dynamics with magneto-transport analysis in quantum wells, including new calculations of defect effects on mobility and noise.

Findings

Defect effects significantly alter electron mobility in quantum wells.

Temperature influences defect capture and relaxation rates.

The model predicts noise characteristics in quantum well devices.

Abstract

The defect corrections to polarization and dielectric functions of Bloch electrons in quantum wells are first calculated. Following this, we derive the first two moment equations from Boltzmann transport theory and apply them to explore defect effects on magneto-transport of Bloch electrons. Meanwhile, we obtain analytically the momentum-relaxation time and mobility tensor for Bloch electrons making use of the screened defect-corrected polarization function. Based on quantum-statistical theory, we further investigate the defect capture and charging dynamics by employing a parameterized physics model for defects to obtain defect wave functions. After this, both capture and relaxation rates, as well as density for captured Bloch electrons, are calculated self-consistently as functions of temperature, doping density and different defect types. By applying the energy-balance equation, the number of occupied energy levels and chemical potential of defects are determined, with which the transition rate for defect capturing is obtained. By using these results, defect energy-relaxation, capture and escape rates, and Bloch-electron chemical potential are obtained self-consistently. At the same time, the Bloch-electron energy- and momentum-relaxation rates, as well as the current suppression factor, are also investigated quantitatively. Finally, by combining all these studies together, the temperature dependence of the Hall and longitudinal mobilities is demonstrated for Bloch electrons in either single- or multi-quantum wells, which can be utilized for quantifying burst noise in transistors and blinking noise in photo-detectors.