The microscopic study of a single hydrogen-like impurity in semi-insulating GaAs

TL;DR

This study investigates the charge dynamics of hydrogen-like impurities in semi-insulating GaAs using muon spin resonance, revealing the role of deep traps and how electric fields influence carrier lifetime and impurity behavior.

Contribution

It provides new insights into the microscopic charge behavior of muonium centers in GaAs and the impact of electric fields on trap neutralization and carrier dynamics.

Findings

Deep hole traps significantly contribute to GaAs compensation.

Electric fields enhance neutralization of deep traps by hot carriers.

Muonium acts as a donor by capturing holes at the As site.

Abstract

The charge dynamics of hydrogen-like centers formed by the implantation of energetic (4 MeV) muons in semi-insulating GaAs have been studied by muon spin resonance in electric fields. The results point to the significant role of deep hole traps in the compensation mechanism of GaAs. Electric-field-enhanced neutralization of deep electron and hole traps by muon-track-induced hot carriers results to an increase of the non-equilibrium carrier life-times. As a consequence, the muonium ($\mu^+ + e^-$) center at the tetrahedral As site can capture the track's holes and therefore behaves like a donor.