Opto-Electronic Properties of Gap1-xSbx Alloys for IR Applications

Abstract

The full potential linearized augmented plane wave (FP-LAPW) method is used to compute structural, electronic, and optical properties of III-V semiconductor ternary alloys GaP_1-xSb_x (0≤x≤1) using first-principle calculations within density functional theory. To calculate the ground state parameters of the structure, the energy exchange-correlation Wu-cohen generalized gradient approximation is employed in the wiek2k program. The Tran–Blaha-modified Becke–Johnson (TB-mBJ) pseudopotential is employed in addition to the Wu-Cohen generalised gradient approximation to achieve a precise bandgap. After this, WC-mBJ is used to examine optical properties such as real and imaginary parts of the dielectric constant, and energy loss. This study illustrates the nonlinear dependency on the various Sb compositions by examining the composition impacts on the bandgap, bulk modulus, and lattice constant. Using WC-mBJ, the estimated band structures for alloys GaP_0.75Sb_0.25, GaP_0.50Sb_0.50, and GaP_0.25Sb_0.75 show direct energy bandgaps of 2.008 eV (617 nm), 1.482 eV (836 nm), and 1.055 eV (1174 nm), respectively. As a result, this material system has enormous potential for use in applications spanning the visible to infrared spectrum.