Tailoring electronic and elastic properties by varying composition of the CuGa1-xAlxS2 chalcopyrite semiconductor

TL;DR

This study uses first-principles calculations to analyze how varying aluminum content and pressure affect the structural, electronic, and optical properties of CuGa1-xAlxS2 chalcopyrite semiconductors, highlighting potential solar cell benefits.

Contribution

It provides new insights into how composition and pressure influence the properties of CuGa1-xAlxS2, aiding in tailored material design for optoelectronic applications.

Findings

Substituting 25% Ga with Al increases visible spectrum absorption by 6%.

Pressure affects band gap and absorption peak positions.

Optical and electronic properties are tunable via composition and pressure.

Abstract

Influence of composition and external hydrostatic pressure on the structural, electronic, and optical properties of the CuGa1-xAlxS2 (x=0, 0.25, 0.5, 0.75, 1.0) chalcopyrite semiconductor was analyzed by means of the first-principles calculations. Dielectric functions and optical absorption spectra were calculated for all considered aluminum concentrations. The pressure coefficients of the calculated band gaps and position of the lowest in energy absorption peaks were extracted from the calculated results. One of the main results is that substitution of 25% of gallium by aluminum (thus forming the CuGa0.75Al0.25S2 semiconductor) increases absorption in the visible part of the solar spectrum by about 6%, which can be important for the solar cell applications.