Localization of electronic states in III-V semiconductor alloys: a comparative study

TL;DR

This study investigates how different impurities affect the localization of electronic states in III-V semiconductor alloys, impacting optical and electronic properties relevant for telecommunication laser applications.

Contribution

It provides a comparative analysis of localization effects due to various impurities in GaAs alloys using first-principles calculations, linking localization to optical and electronic performance.

Findings

Localization varies with impurity type and influences band gap and alignment.

Localization correlates with photoluminescence broadening and carrier mobility.

Impurity formation energies relate to alloy growth challenges.

Abstract

Electronic properties of III-V semiconductor alloys are examined using first principles with the focus on the spatial localization of electronic states. We compare localization at the band edges due to various isovalent impurities in a host GaAs including its impact on the photoluminescence line widths and carrier mobilities. The extremity of localization at the band edges is correlated with the ability of individual elements to change the band gap and the relative band alignment. Additionally, the formation energies of substitutional defects are calculated and linked to challenges associated with the growth and formability of alloys. A spectrally-resolved inverse participation ratio is used to map localization in prospective GaAs-based materials alloyed with B, N, In, Sb, and Bi for 1.55 $\mu$m wavelength telecommunication lasers. This analysis is complemented by a band unfolding of the electronic structure and discussion of implications of localization on the optical gain and Auger losses. Correspondence with experimental data on broadening of the photoluminescence spectrum and charge carrier mobilities show that the localization characteristics can serve as a guideline for engineering of semiconductor alloys.