Strain tuning of optical and thermoelectric properties of monolayer BAs.

This study investigates the electronic, optical and thermoelectric properties of monolayer boron arsenide (BAs) using a fifth-nearest-neighbor tight-binding model based on density functional theory (DFT) calculations, with a particular focus on the effects of biaxial strain to tune its characteristics for optoelectronic and thermoelectric applications. The results show that monolayer BAs possesses a direct band gap of approximately 1.2 eV at the K-point, maintaining its semiconducting nature across a strain range of - 8% to + 8%. The band gap is observed to decrease under compressive strain and increase under tensile strain. Optical spectra exhibit two distinct peaks in the infrared and ultraviolet regions, corresponding to transitions between the valence and conduction bands at the K and M points, which are significantly modulated by strain. Specifically, compressive strain induces a red-shift in these optical peaks, while tensile strain causes a blue-shift. The strain-dependent electronic modifications also significantly influence the thermoelectric properties of BAs, leading to enhancing under compressive strain and decreasing with tensile strain.