Theoretical investigations of optoelectronic and thermoelectric properties of the XIn2O4 (X = Mg, Zn, Cd) spinel oxides

Abstract

The spinel oxides have received remarkable attention in recent years for being promising materials for optoelectronic and thermoelectric applications. In this paper, the thermodynamic stability of the XIn2O4 (X = Mg, Zn, Cd) spinels is examined by calculating the formation energy whereas the mechanical stability is evaluated by Born mechanical stability criteria. Our results indicate adequate thermodynamic and mechanical stability of the studied spinels. Ductile behavior of these materials is established through Pugh's and Poisson's ratios. The bandgaps of magnitudes 4.0 eV, 2.79 eV, and 2.21 eV have been calculated respectively for MgIn2O4, ZnIn2O4 and CdIn2O4 by modified Becke and Johnson (mBJ) exchange potential. The optical spectra of dielectric constants, refraction, absorption and other related parameters are determined to explore their potential for optoelectronic applications. Furthermore, thermoelectric properties are investigated in terms of thermal to electrical conductivities, Seebeck coefficients, and figures of merit (ZT). The high ZT of magnitude 0.84, 0.74, 0.79 are observed for MgIn2O4, ZnIn2O4 and CdIn2O4 that highlight important of these materials' potential applications in thermoelectric generators and other thermal energy conversion devices.