Investigation of structural, mechanical, electronic and optical responses of Ga doped aluminum arsenide for optoelectronic applications: By first principles.

Owing to the rapidly increasing performance of ternary semiconductors; Aluminium Gallium Arsenide (AlGaAs; x = 0, 0.25, 0.50, 0.75) has been studied by first-principles calculations in Cambridge Serial Total Energy Package (CASTEP-Code). Density functional theory in the frame of full potential linear augmented plane wave (FP-LAPW) is used. The structural, electronic, and optical behavior of the Zinc Blend (ZB) structure of AlAs with Ga impurity was computed by using generalized gradient approximation (GGA) as exchange potential and Perdew-Burke-Ernzerhof (PBE) as functional. Changes in lattice parameters (a), bulk modulus (66.07-76.85), hardness (5.79-8.91) and machinability (1.36-1.46), band gap energy (E), and optical properties are computed and discussed in this work. Lattice parameters and elastic constants showed excellent agreement with the reported data whereas some properties were found to excel much more than the theoretical reports. Remarkable bandgap reduction from 1.7eV to 0.28eV is very encouraging in its low-energy applications in UV and visible ranges. Real (Re) and Imaginary (Img) parts of the dielectric function and refractive index shifts towards lower energy values show good agreement with those of theoretical and experimental works. We contribute to the knowledge and characterization of AlGaAs facilitating its integration into various technological advancements such as photovoltaic, laser, diodes, and high-frequency transistors.