Investigation of the electronic, structural, optical and thermoelectric properties of ternary chalcopyrite ACuS2(A=Al, Ga and In): Ab initio study

Abstract

In the present work, the structural, electronic, optical and thermoelectric properties of the ternary chalcopyrite compounds defined by ACuS2(A=Al, Ga, In) has been performed by density functional theory (DFT) combined with Boltzmann transport theory. Based on the generalized gradient (GGA) approach, the stability accompanied with the structural parameters of the studied structure compounds was evaluated. Furthermore, modified Becke-Johnson exchange potential (TB-mBJ) was adopted for the exchange correlation potential in order to prove the electronic and optical features of ACuS2(A=Al, Ga and In). The plotted density of state, band structure, distribution charge density of the ACuS2(A=Al, Ga and In) component, with dielectric function, reflectivity, Seebeck coefficients, electrical and thermal conductivity are obtained and discussed. Our result reveal, for electronic properties, that all components exhibit p-type semiconductor with direct band gap, with 1.51 eV for GaCuS2. The chemical bonding analysis shows the presence of ionic bonding between Al/In/Ga and S. The calculated dielectric function and the absorption coefficient indicate that InCuS2 followed by GaCuS2 display an excellent absorption in the visible range with low reflectivity. The evaluated results are in excellent agreement with available experimental and theoretical data. The physical properties of the novel ACuS2 (A=Al, Ga and In) compound show promising candidate toward photovoltaic, optoelectronic and thermoelectric device.