Exploring the electronic, optical, and thermometric properties of novel AlCuX2 (X = S, Se, Te) semiconductors: a first-principles study

In the current study, we investigated the structural, electronic, optical, and thermoelectric properties of three chalcopyrite materials AlCuX2 (X = S, Se, and Te) employing the full-potential linearized augmented plane waves (FP-LAPW) within the density functional theory (DFT). The generalized gradient approach (GGA-PBE) and the modified Becke–Johnson exchange potential (mBJ-GGA) approximations were employed to calculate the exchange and correlation potentials. The stability of the studied compounds and their structural parameters was evaluated. Our findings revealed that these studied compounds exhibit a semiconductor character with a direct band gap. The two compounds AlCuTe2 and AlCuSe2 displayed excellent visible absorption with limited reflectivity. The optical characteristics of the AlCuTe2 compound better as compared to the AlCuS2 and the AlCuSe2 compounds, suggesting it a potential candidate for nonlinear optical applications. The Boltzmann transport theory was employed to analyze the thermoelectric properties. The calculation of Seebeck and hall coefficients confirmed the p-type nature in these compounds. According to the thermoelectric results, the AlCuS2 compound possesses a high electrical conductivity, Seebeck coefficient (S), and figure of merit (ZT) with low thermal conductivity. The computed results perfectly agree with the reported experimental and theoretical data. Such structures with suitable band gaps can absorb a sufficient amount of light, making them potential candidates for solar cells applications to satisfy energy requirements.