Correlation between structural, electronic, and optical response of Ga-doped AlSb for optoelectronic applications: a first principle study

Density functional theory is used to examine structural, electronic, and optical properties of Al1−xGaxSb by employing the full potential linear augmented plane wave method. Structure parameters as lattice constants, bulk modulus, pressure derivatives, ground-state energy, and volume optimization are employed by generalizing gradient approximation (GGA-PBE). A remarkable deviation of lattice constant and Bulk modulus is observed by adding the concentration of Ga atoms in AlSb. Electronic properties like band structure and density of states are calculated by GGA-PBE with the addition of the Tran–Blaha-modified Becke–Johnson (TB–mBJ) approach. The calculated results demonstrate that the binary compound AlSb shows an indirect (Γ–X) bandgap and is optically inactive. By increasing Ga concentration in AlSb at varying percentage, bandgap transforms from indirect to direct (Γ–Γ) and the material becomes optically active. There is a marked change in optical behavior in dielectric constant, optical conductivity, reflectivity, refractive index, and absorption coefficient, and energy loss by adding Ga concentration in AlSb. Obtained results are analyzed with experimental data and employed as a gateway to suggest that material is the best candidate for optoelectronic applications. Graphical abstract