"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

Effect of crystallization on the optical properties of Se0.8S0.2 amorphous films

M. ABDEL RAFEA1,* , HUDA FARID1

Affiliation

  1. Institute of Advanced Technology & New Materials, Mubarak City for Scientific Research & Technology Applications P.O. Box 21934 Universities and Research Centers District, New Borg El Arab City, Alexa

Abstract

Se0.8S0.2 glassy films of thickness 583 nm have been prepared by thermal vacuum evaporation technique. Annealing of the films shows that the crystallization process starts at T= 333 K and nanostructured film is formed. The increase of the annealing temperature to 373 K increases the crystallite size to 24 nm. Orthorhombic crystalline system was identified for the annealed films. SEM micrographs show that films consist of two parallel surfaces and the thickness was determined by cross section imaging. The optical transmittance is characterized by interference patterns as a result of these two parallel surfaces, besides their average value at longer wavelength decreases as a result of annealing process. The band gap, Eg is red shifted due to crystallization by annealing. The change of Eg from the amorphous value to the crystalline one is not sharp. A relatively slow decrease in Eg intermediate annealing temperature was observed. This change was explained in the energy gap confinement behavior of the nanostructured films and the phenomena was discussed in the Brus`s model. The optical refractive index increases suddenly when the system starts to be crystallized by annealing..

Keywords

Chalcogenide glasses, Thermal vacuum evaporation, Annealing, Crystallization, Nanostructured films, Optical properties.

Submitted at: March 22, 2008
Accepted at: July 10, 2008

Citation

M. ABDEL RAFEA, HUDA FARID, Effect of crystallization on the optical properties of Se0.8S0.2 amorphous films, Journal of Optoelectronics and Advanced Materials Vol. 10, Iss. 8, pp. 2129-2133 (2008)