Engineering of the band gap and optical properties of InxGa1−x(As/Sb) via across composition alloying for solar cell applications using density functional theory-based approaches

Abstract

The optoelectronic properties of InxGa1−x(As/Sb) are analyzed using density functional theory by employing a modified potential scheme of Trans and Blaha as developed in WIEN2k code. The indium doping in GaAs and GaSb tune the band gap from 1.56 to 0.43 eV and 0.82 to 0.30 eV, respectively, which highlights their significance for solar cell related applications. The optical characteristics are assessed by studying the dielectric constant, refraction, absorption, optical conductivity and optical loss of light energy. The static dielectric constant related to the optical band gap through Penn’s model and with static refractive index = n2(0) increase consistently between the calculated results. The maximum absorption and small optical loss factor for visible to near UV regions can enhance the optical efficiency for solar cell and optoelectronic applications. Moreover, higher optical conductivity within 3.5–4.5 eV allows forward current, which is attractive for practical applications.