Investigation of optoelectronic & thermoelectric features of ZnCrX2 (X = S Se Te) chalcopyrite semiconductor using mBJ potential

Abstract

In the present investigation, we have examined the structural, optoelectronic and thermoelectric properties of the compound ZnCrX2 (X = S, Se, Te) using the full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA-PBEsol) and the modified Becke–Johnson (mBJ) implemented on Wien2k code. By calculating the electronic structure, we observed that the indirect band gap was 1.76 eV, 1.68 eV, and 1.59 eV, for these selected compounds and the type of chemical bonding was ionic between Zn-X and Cr-X. For the three ternary chalcopyrites their optical properties including optical conductivity, complex dielectric functions, complex refractive index, reflectivity, energy loss, and absorption coefficient were examined. The calculated optical conductivity indicates that the studied compounds are suitable for optoelectronic applications as they have good absorbance and less energy loss in the low energy range of the electromagnetic spectrum. For ZnCrTe2, the maximum reflectivity was in the low energy range (0.48 or 48% at 9 eV). The BoltzTrap code was executed for the calculation of the thermoelectric properties and thermal efficiency of the compounds investigated, depending upon the Seebeck coefficient, thermal conductivity and electrical conductivity. The high value of the figure of merit and the Seebeck coefficient (260 uV/k) defines the high efficiency of the materials studied. Hence, the studied chalcopyrite compounds offer applications in solar cell devices and p-type semiconducting nature predictive in transport investigations.