Analysis of ternary AlGaX2(X = As, Sb) compounds for opto-electronic and renewable energy devices using density functional theory

Abstract

Based on the First-principles calculations, we have investigated the opto-electronic properties of AlGaX2(X = As, Sb). We find that the AlGaX2(X = As, Sb) is energetically stable due to lower formation enthalpy. Additionally, the dynamical stability is also confirmed by phonon calculation and found no-imaginary frequencies in the phonon-spectra. Interestingly, both AlGaAs2 and AlGaSb2 compounds possesses semiconductor nature with a direct bandgap of 1.40 eV and 0.70 eV, respectively. For the technological applications of AlGaX2(X = As, Sb), we have analyzed optical properties in terms of absorption of photon energy and polarization. A strong absorption peaks are observed in the visible region. Moreover, the thermoelectric properties are calculated in terms of electrical/thermal conductivities, Seebeck coefficient, and figure of merit (ZT). Thermal parameters are critical for determining a material’ thermal stability across the wide range of temperatures. We expect that our calculated properties of AlGaAs2 and AlGaSb2 compounds could pave a new route for the applications in the optoelectronics and thermoelectric devices.