The high thermal conductivity of boron arsenide (BAs) makes it a promising material for optoelectronic applications in which thermal management is central. In this work, we study the finite temperature optoelectronic properties of BAs by considering both electron-phonon coupling and thermal expansion. The inclusion of electron-phonon coupling proves imperative to capture the temperature dependence of the optoelectronic properties of the material, while thermal expansion makes a negligible contribution due to the highly covalent bonding character of BAs. We predict that with increasing temperature the optical absorption onset is subject to a red shift, the absorption peaks become smoother, and the phonon-assisted absorption at energies below those of the optical gap has a coefficient that lies in the range 10−3 to 10−4 cm−1. We also show that good agreement with the measured indirect band gap of BAs is only obtained if exact exchange, electron-phonon coupling, and spin-orbit coupling effects are all included in the calculations.
@article{arxiv.1904.11511,
title = {Finite temperature optoelectronic properties of BAs from first principles},
author = {Ivona Bravić and Bartomeu Monserrat},
journal= {arXiv preprint arXiv:1904.11511},
year = {2019}
}