Nitrogen local electronic structure in Ga(In)AsN alloys by soft-X-ray absorption and emission: Implications for optical properties

TL;DR

This study uses soft-X-ray spectroscopies to analyze the local electronic structure of nitrogen in Ga(In)AsN alloys, revealing deviations from crystalline GaN that impact optical efficiency and how indium incorporation can improve electronic properties.

Contribution

It provides detailed insights into the local electronic structure of nitrogen in Ga(In)AsN alloys using soft-X-ray techniques, highlighting the effects of indium incorporation on electronic states.

Findings

Depletion of valence band maximum at N sites reduces optical efficiency.

In-rich N environments like In4N show improved electronic structure.

Resonant inelastic X-ray scattering reveals k-character in alloy states.

Abstract

Soft-X-ray emission and absorption spectroscopies with their elemental specificity are used to determine the local electronic structure of N atoms in Ga(In)AsN diluted semiconductor alloys (N concentrations about 3%) in view of applications of such materials in optoelectronics. Deviations of the N local electronic structure in Ga(In)AsN from the crystalline state in GaN are dramatic in both valence and conduction bands. In particular, a depletion of the valence band maximum in the N local charge, taking place at the N impurities, appears as one of the fundamental origins of reduced optical efficiency of Ga(In)AsN. Incorporation of In in large concentrations forms In-rich N local environments such as In4N whose the electronic structure evolves towards improved efficiency. Furthermore, a k-character of some valence and conduction states, despite the random alloy nature of Ga(In)AsN, manifests itself in resonant inelastic X-ray scattering.