First-principle study of the optoelectronic properties of GaxIn1-xBiyP1-y quaternary alloys lattice-matched to InP for telecommunication applications

In this work, we present a theoretical investigation of the structural and optoelectronic properties of Ga x In 1-x Bi y P 1-y quaternary alloys lattice-matched to InP using the full-potential linearized augmented plane wave approach based on the functional theory of density. The local density approximation (LDA) and the generalized gradient approximation of Wu–Cohen (WC-GGA) have been used for calculating the structural properties of Ga x In 1-x Bi y P 1-y quaternaries. The lattice matching condition and the range of ( x, y) concentrations for which the quaternary alloys are lattice-matched to InP substrate were determined. It is found that the calculated lattice constants of Ga x In 1-x Bi y P 1-y for all selected concentrations ( x, y) are about 5.9 Å, which are in good agreement with the experimental value of the lattice constant of InP (5.869 Å). The electronic property calculations are executed via EV-GGA and TB-mBJ approximations. The calculated band structures show that Ga x In 1-x Bi y P 1-y quaternaries have semiconductor character and exhibit a direct band gap, for all selected concentrations ( x, y). In addition, the optical properties were calculated and discussed in detail. And also, the optical band gaps of quaternaries were determined using Tauc's method. We observed that the Ga x In 1-x Bi y P 1-y quaternaries cover the wavelength ranging from 0.911 to 2.456 µm while maintaining a lattice match to the InP substrate. The obtained results reveal that these quaternaries are suitable candidates for telecommunication applications.