"

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.

Photoinduced changes of the optical parameters of thin films from Ge30.8As5.7S63.5 glass

F. YAKUPHANOGLU1, D. ARSOVA2,* , E. VATEVA2

Affiliation

  1. Department of Physics, Faculty of Arts and Sciences, Firat University, Elazig, Turkey
  2. Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria

Abstract

Extremely high irreversible changes of the optical parameters have been found after long time illumination of thin films thermally evaporated from Ge30.8As5.7S63.5 glass, which belongs to the Ge2As3-AsS3 line. Illumination of virgin films leads to a blue shift of the absorption edge, photo-bleaching (PB). Changes of the optical band gap, Eg up to about 600 meV (~27%), of the refractive index, n up to 0.2 (~9.5%), as well as the thickness increase ~70 nm (11%) have been obtained. The dependences of the parameters of the irreversible PB on the film thickness (between 0.4 - 1.4 μm) and the time of illumination (up to 3h) have been investigated. The magnitude of the irreversible PB is compared with that of the irreversible thermo-bleaching after annealing near to the glass transition temperature, as well as with that of the reversible photo-darkening of the annealed films. The reasons for the appearance of such high photo-induced changes, which are interesting for practical uses, are discussed..

Keywords

Chalcogenide films, Refractive index, Optical band gap.

Submitted at: Nov. 1, 2006
Accepted at: Feb. 15, 2007

Citation

F. YAKUPHANOGLU, D. ARSOVA, E. VATEVA, Photoinduced changes of the optical parameters of thin films from Ge30.8As5.7S63.5 glass, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 2, pp. 334-336 (2007)