Orchestrating the impact of antisites and vacancy defects on the elastic and optoelectronic properties of boron arsenide

Abstract

Context: Cubic boron arsenide (c-BAs), a semiconducting material with ultra-high thermal conductivity and carrier mobilities, has been studied using first-principles calculation. This study examined the elastic and optoelectronic properties of c-BAs. The challenge of subphase boron (B) formation in bulk form owing to the volatile nature of arsenic (As) makes it mandatory to calculate its optoelectronic properties, by producing vacancies and antisite defects with B_As (As atom on a B site) and As_B (B atom on an As site). The mechanical properties including bulk (B), shear (G) moduli, and Poison's ratio of all the systems were studied. It was found that mechanical instability of the structure is observed for the overall vacancy creation, arsenic substitution, and mutual antisite defects. Further, pristine c-BAs showed an indirect bandgap of 1.48 eV. Defect formation reduces the bandgap and shifts the absorption peaks, which improves the overall optoelectronic properties of the host material. In addition, B vacancy formation shows the maximum optical absorption and reflectivity and low energy loss, suggesting its potential applications for optoelectronic devices. The obtained anticipated data from this study is for the optoelectronic and elastic properties of c-BAs, for the device applications in photonics and electronics.

Method: In this paper, the elastic and optoelectronic properties of the pristine and defected c-BAs were systematically investigated using the Spanish Initiative for Electronic Simulations with Thousands of Atoms (SIESTA). The SIESTA program uses pseudopotentials in the norm-conserving nonlocal forms and pseudo-atomic orbital (PAO) basis set with a double-zeta potential (DZP) which are fundamental for calculating the Hamiltonian and overlap matrices in O(N) operations.

Keywords: Bulk modulus; Density functional theory; Dielectric constant; Elastic constants; Electronic properties; Optical properties; Optoelectronic.