Structural and Optical Constants of Annealed As47.5Se47.5Ag5 Film using DSC Transformation Curve

E.R. Shaabana, M.A. Abdel-Rahimb, M.N. Abd-el Salamb, c, Mansour Mohamedb, A.Y. Abdel-Latiefb, El Sayed Yousefd, e aPhysics Department, Faculty of Science A1-Azhar University, Assiut 71542, Egypt bPhysics Department, Faculty of Science, Assiut University, Assiut 71516, Egypt cHigh Institute for Engineering and Technology, El-Minya 61768, Egypt dPhysics Dep., Faculty of Science, King Khalid University, P.O. Box 9004, Abha, Saudi Arabia eResearch Center for Advanced Materials Science (RCAMS), King Khalid University, Abha 61413, P.O. Box 9004, Saudi Arabia

Received: April 27, 2018; in final form September 11, 2018

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The effect of thermal annealing process on both structural and optical properties of amorphous As47.5Se47.5Ag5 thin films was studied. The X-ray diffraction studies exhibit that the crystallinity was improved by increasing the annealing temperature. Further, the crystallite size and the crystallinity increase whereas dislocation density and strain decrease with increase of annealing temperatures. The optical constants of the as-prepared and annealed of As47.5Se47.5Ag5 thin films were calculated using envelope method. The optical absorption data in these films were successfully describes by Tauc's relation which exhibit the indirect transitions for as-prepared sample and allowed direct transition for annealed sample above onset temperature Tc. It is evident that the energy gap Egopt decreases and the localized states Ee increases as a function annealing temperature. The dispersion of the refractive index n for these films was discussed using the single oscillator model proposed by the Wemple-DiDomenico relationship.

DOI:10.12693/APhysPolA.135.401 topics: As47.5Se47.5Ag5 thin films, annealing temperatures, XRD, optical properties, single oscillator \\m{parameters}