Impact Factor (2025): 6.9
DOI Prefix: 10.47001/IRJIET
A thin film's microstructural and optical properties are essential for the development of optoelectronic devices. As a result, the thermal evaporation of selenium-rich Ge15Se85 (SR-GeSe with thickness of 250 nm) thin films was investigated for improving these properties. The films fabricated in a pure nitrogen-rich atmosphere were annealed in the thermal temperature range between 200oC and 300oC for 30 minutes. The microstructural, compositional, and optical characteristics of these films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with the energy dispersive X-ray analysis (EDXA), and UV-Vis-INR spectrophotometers. In accordance with the XRD patterns, the as-prepared films were in an amorphous state, while the annealed films were in the polycrystalline style. In annealed films, crystalline phases with hexagonal orientations were formed. Crystallographic parameters were significantly affected by thermally induced effects. As seen from the surface morphology, the films were nearly densely packed, homogeneous, smooth, uniform, and free from holes and voids. In the thin films of SR-GeSe, the band gap and Urbach energies behaved oppositely. Amorphous-crystalline transitions and the Mott-Davis model were used to explain the studied optical properties. The single oscillator for Wimple-DiDomenico (WDD) model described the refractive index scattering whose parameters were determined as a function of annealing temperature. By adjusting the thermal annealing process, the microstructural and optical properties of SR-GeSe thin films were improved, indicating their suitability for thermo-optic applications. On the other side, the electronic parameters including the energies of Plasmon, Penn, Fermi and the number of active electrons were computed.
Country : Yemen
IRJIET, Volume 7, Issue 3, March 2023 pp. 36-49