Thermal annealing effect on the structural and the optical properties of Nano CdTe films

摘要

Structural and optical properties of as-prepared and annealed thermal evaporated CdTe films were investigated. The annealing temperature (373-523 K) affects both structural and optical parameters. Polycrystalline nature with preferred (1 1 1), (2 0 0) and (2 2 0) orientations was released, the corresponding two theta is 23.15 degrees, 27.42 degrees and 40.26 degrees respectively. Structural parameters as dislocation density, interplaner distance, the number of crystallites per unit surface area, lattice constant, crystallite size and strain could be determined as a function of annealing. The results confirm the films nanostructure property. The optical gap, refractive index, dielectric constant and optical conductivity increase as a function of annealing. These effects were attributed to the nano structural property and the partial reduction of the defect density. (C) 2015 Elsevier GmbH. All rights reserved.