DFT and experimental approach: Ca substituted strontium oxide thin films for optoelectronics
摘要
Density functional theory calculations were performed using the Tran-Blaha modified Becke-Johnson exchange–correlation functional, to study the structural, electronic, optical, and thermoelectric properties of Ca-substituted SrO. For comparative simulation and experimental investigations, Ca-substituted SrO thin films were grown using a chemically derived technique. X-ray diffraction analysis revealed prominent diffraction peaks indexed as the (111) and (200) planes of the cubic phase of SrO. Surface analysis demonstrated the trend of increasing porosity and decreasing grain size at higher calcium substitution levels. The evaluated density of states of SrO are primarily influenced by Sr-d and O-p orbitals, while the substitution of Ca introduced a hybridization of O-p, Sr-d, and Ca-d orbitals. The simulated optical band gap of SrO was observed as 5.02 eV which experienced a variation with Ca-substitution. The thermoelectric properties indicated enhanced electrical conductivity for Ca-substituted SrO compositions. The key findings of simulations and experiment are consistent, and the improved properties suggest these compositions suitable for thermoelectric and optoelectronic applications.