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Effects of annealing on structural and optical properties of Ge20Se70Sn10 thin films for optoelectronic applications

2020; Elsevier BV; Volume: 549; Linguagem: Inglês

10.1016/j.jnoncrysol.2020.120353

1873-4812

Alaa M. Abd‐Elnaiem, Samar Moustafa, Ahmed Abdelraheem, M.A. Abdel-Rahim, A.Z. Mahmoud,

Chalcogenide Semiconductor Thin Films

This study reposts the influence of annealing temperature (TA) on structural and optical properties of ~150 nm thick Ge20Se70Sn10 films. Amorphous Ge20Se70Sn10 films were prepared via thermal evaporation of bulk Ge20Se70Sn10 glass. The films were then annealed between 503 and 703 K leading to the formation of Sn0.5Ge0.5Se and Ge4Se9 phases. For samples annealed at TA ≥ 653 K, Sn0.5Ge0.5Se phase decomposed to form Ge4Se9 phase. Based on the reflectance R(λ) and transmittance T(λ) studies, various optical constants such as the refractive index and extinction coefficient, real and imaginary of dielectric constants among others were investigated. Linear parameters such as the optical band gap decreased (~0.94 eV) as the annealing temperature increased while the Urbach energy reveals contrasting behavior. The oscillator energy and the dispersion energy decreased with increasing TA. Other electronic parameters such as the Penn gap, electronic polarizability, Fermi energy, VELF, and SELF functions are significantly influenced by TA.