Proposal of new spinel oxides semiconductors ZnGaO2, [ZnGaO2]:Mn3+ and Rh3+: ab-initio calculations and prospects for thermophysical and optoelectronic applications

Transparent conducting oxides (TCOs) of semiconductor family gained significant attention due to increasing trends in the optoelectronic and thermo-physical applications. In current work, we reported electronic, optical, transport and thermodynamical properties of spinel oxides ZnGaO2, [ZnGaO2]:Mn3+ and [ZnGaO2]:Rh3+ compounds. Based on DFT, we employed first-principles calculations implemented in Wien 2k using the modified-Becke-Johnson (mBJ) on parent spinel and generalized-gradient-approximation plus Hubbard potential U (GGA + U) on doped materials, respectively. The calculated band structure shows insulating nature of parent compound, while doped material observed semiconducting nature contains direct band gap for both spin channels with band gaps of [ZnGaO2]:Mn3+ (0.59 up, 2.4 eV dn) and [ZnGaO2]:Rh3+ (2.1 eV up/dn) respectively. The electronic and optical results reveal that hybridization occurred mainly due to O-p/Zn, Mn-d, Rh-d and Ga-s orbitals. It is analyzed that Mn-doped material shows good absorption in the visible region while other are good in UV region. The effective masses of spinel oxides are also computed at high symmetry directions hence varied nonlinearly with the doping. The stability of materials is checked by calculating formation energies which indicate Mn-doped spinel oxide is most stable as that of others. The thermoelectric properties of spinel oxides were carried out by Post-DFT (Boltztrap) calculations. Large values of Seebeck coefficient and power factor of Mn-doped spinel oxide indicate that this material can be used for thermoelectric devices. The thermodynamical properties are calculated by quasi-harmonic Debye model implemented in GIBBS 2 code. Moreover, the pressure and temperature dependence of all (TD) parameters of investigated spinel oxides are analyzed using quasi-harmonic Debye model. [Display omitted] •We investigated structral, optoelectronic and tranport properties of spinel oxides Fe3BO6 and Rh0.08Fe0.92BO6 compounds.•The approximation used for these calculations was generalized gradient plus Hubbard potential (GGA+U).•The band structure of parent compound for spin up shows insulating nature while other channel is semiconducting nature (4.181 eV Up/2.41 eV Dn).•The optical dispersion exhibits strong absorption in the UV region, for both materials.•The transport parameters are computed by Post-DFT approximations based on rigid band approach in Boltzmann code.