The electronic and optical properties of quaternary BxGa1−xAs1−ySby alloys with low boron concentration: A first-principles study

Highlights: ► The electronic properties of BGaAsSb alloy lattice matched to GaAs are studied. ► The alloy exhibits the direct band gap character. ► The band gaps have a slight reduction with increasing B content. ► Optical properties of BGaAsSb are analyzed in details. -- Abstract: We have performed the first-principles density functional calculations of the electronic and optical properties of quaternary BxGa1−xAs1−ySby alloy lattice-matched to GaAs with boron concentration x = 3.125% and 6.25%. All the calculations have been performed after geometric optimization. The calculated results show that BxGa1−xAs1−ySby alloys have the direct band gap. The density of states of GaAs and BGaAsSb were analyzed. In addition, the optical properties have been studied with a scissors operator. The effects of B and Sb incorporation on the dielectric function, reflectivity, refractive index, absorption coefficient and energy loss function of lattice-matched BxGa1−xAs1−ySby alloys in the photon energy range of 0–20 eV are also discussed in detail. We find our calculated results can be in good agreement with the available experimental values