DFT and experimental study of Mg substituted strontium oxide for optoelectronic applications

Abstract

Strontium oxide and magnesium-doped compositions were analyzed using density functional theory to explore their electronic, thermoelectric, and optical properties. Magnesium-doped SrO thin films with various concentrations were experimentally prepared on silicon substrates using the sol-gel spin-coating technique. Structural analyses confirmed the stable single-phase cubic crystalline structure, unaffected by doping. Electronic studies revealed a reduced band gap and the formation of states near the Fermi level, improving charge carrier transport. The thermoelectric evaluation indicated enhanced electrical conductivity that observed for pure SrO as 4.42 × 10¹⁹ (Ω m s)⁻¹, whereas 9.43 × 10¹⁹ (Ω m s)⁻¹ for maximum Mg containing composition. The lowered thermal conductivity is contributing to superior thermoelectric performance. Optical analyses demonstrated improved absorption and reduced optical band gap, affirming enhanced light interaction capabilities. The highest refractive index and real epsilon values were recorded at the higher energy regimes approximately 2.94 and 12.89, respectively, for composition containing maximum dopant content. The optical band gap of SrO was calculated as 2.50 eV and found to decrease with increment of Mg substituting concentration. Experimental results showed strong alignment with theoretical predictions, underscoring the potential of Mg-doped SrO thin films as promising candidates for advanced optoelectronic and thermoelectric applications.