Cross-sectional imaging of sharp Si interlayers embedded in gallium arsenide

TL;DR

This study uses first-principles calculations to analyze the electronic properties of Si-doped GaAs surfaces, revealing STM image features consistent with experimental observations of Si complexes.

Contribution

It provides new insights into the electronic structure and STM signatures of Si interlayers in GaAs, especially in self-compensating doping regimes.

Findings

Simulated STM images match experimental bias-dependent contrast.

Identified Si complexes responsible for specific STM features.

Enhanced understanding of Si doping effects in GaAs.

Abstract

We investigate the electronic properties of the (110) cross-sectional surface of Si-doped GaAs using first-principles techniques. We focus on doping configurations with an equal concentration of Si impurities in cationic and anionic sites, such as occurring in a self-compensating doping regime. In particular we study a bilayer of Si atoms uniformly distributed over two consecutive (001) atomic layers. The simulated cross-sectional scanning tunneling microscopy images show a bright signal at negative bias, which is strongly attenuated when the bias is reversed. This scenario is consistent with experimental results which had been attributed to hitherto unidentified Si complexes.