Investigation of TiO ₂ /SnO ₂ /MgO Mixed Metal Oxide Nanostructures Thin Films for Sustainable Optoelectronic Applications

TiO 2 /SnO 2 /MgO mixed metal oxide thin films were deposited on glass substrates using the electron beam evaporation technique with an average thickness of 250 nm. Post-deposition annealing was carried out at 400 ℃ to examine its effect on the structural, optical, surface, and electrical characteristics of the films. XRD results indicated an increase in diffraction peak intensity after annealing, suggesting improved crystallinity and reduced structural disorder within the mixed oxide system. Optical analysis revealed a widening of the band gap from 4.14 eV to 4.27 eV, which may be associated with modifications in the microstructure and defect concentration after thermal treatment. Photoluminescence (PL) results show that annealing at 400 ℃ has greatly influenced the defect structure and recombination behavior of the TiO 2 /SnO 2 /MgO thin films. FE-SEM micrographs demonstrated homogeneous film distribution with good substrate adhesion, while EDS analysis confirmed the presence of Ti, Sn, Mg, and O elements in the deposited films. AFM studies further revealed noticeable changes in surface morphology and roughness following annealing. Electrical measurements obtained from Hall Effect and I-V characterization confirmed n-type semiconducting behavior with improved carrier transport properties. The prepared TiO 2 /SnO 2 /MgO thin films exhibit strong potential for application in environmentally sustainable optoelectronic devices.