Electronic, optical and thermoelectric properties of CaO mono- and bi-layers: Theoretical comparative investigation

Abstract

The nano technology development requires efficient multifunctional low dimensional materials. In this work, the full-potential linearized augmented plane wave (FP-LAPW) method and semiclassical Boltzmann transport theory are applied to investigate the structural, electronic, optical and thermoelectric properties of the CaO monolayer and bilayers with AA and AB stacking. These two-dimensional (2D) materials are indirect gap semiconductors with band gap of 2.619, 2.290 and 2.857 eV, respectively. CaO monolayer and bilayers appear to be prospective materials for applications in the ultraviolet detector and absorber of the optoelectronic devices provided that they show wide absorption band with high absorption coefficient. Simulations demonstrate that the in-plane polarized incident light may be more efficient to excite the electronic transitions than the perpendicular polarization. Finally, the thermoelectric properties of layers at hand including Seebeck coefficient, electrical conductivity, electronic thermal conductivity and power factor are determined and discussed. Studies suggest that the AA-stacking may be the most promising candidate for the thermoelectric applications. Results presented here may be a good theoretical guidance for the low-dimensional wide band gap semiconductors.