Investigation of Pressure Effect on Structural and Optoelectronic Properties of Al0.75Sc0.25P Structure Using Density Functional Theory

Abstract

The structural, electronic, and optical properties of AlP and Al_0.75Sc_0.25P were investigated through a series of under hydrostatic pressures from 0 to 15 GPa using Density Functional Theory (DFT) with the PBE-GGA functional. This pressure range was chosen to retain the zinc-blende structure and avoid phase transition. The lattice constant for Al_0.75Sc_0.25P decreased from 5.620 Å to 5.350 Å. The direct band gap decreased slightly from 1.833 eV to 1.814 eV. Conversely, the indirect band gap increased from 2.52 eV to 2.67 eV. The optical properties demonstrated nonlinear dependence on pressure; the static dielectric constant and refractive index both decreased before increasing. The Sc concentration (x = 0.25) was chosen to enhance properties without significant structural distortion. Despite experimental challenges, including AlP instability in humid conditions and high-pressure limitations, this study provides valuable insights into the pressure-tunable behavior of AlP-based materials for potential optoelectronic applications.