Band structure and carrier effective masses of boron arsenide: effects of quasiparticle and spin-orbit coupling corrections

TL;DR

This study uses advanced theoretical methods to analyze boron arsenide's electronic structure, revealing its indirect band gap, effective masses, dielectric properties, and exciton stability, aiding future experimental and device research.

Contribution

It provides comprehensive theoretical insights into BAs's electronic and optical properties, including quasiparticle and spin-orbit effects, which were not previously detailed.

Findings

BAs has an indirect band gap of 2.049 eV.

Holes have smaller effective masses than electrons.

Excitons in BAs are stable at room temperature.

Abstract

We determine the fundamental electronic and optical properties of the high-thermal-conductivity III-V semiconductor boron arsenide (BAs) using density functional and many body perturbation theory including quasiparticle and spin-orbit coupling corrections. We find that the fundamental band gap is indirect with a value of 2.049 eV, while the minimum direct gap has a value of 4.135 eV. We calculate the carrier effective masses and report smaller values for the holes than the electrons, indicating higher hole mobility and easier p-type doping. The small difference between the static and high frequency dielectric constants indicates that BAs is only weakly ionic. We also observe that the imaginary part of the dielectric function exhibits a strong absorption peak, which corresponds to parallel bands in the band structure. Our estimated exciton binding energy of 43 meV indicates that excitons are relatively stable against thermal dissociation at room temperature. Our work provides theoretical insights on the fundamental electronic properties of BAs to guide experimental characterization and device applications.