GaGeTe films as phase-change optical recording media

Abstract

Ga 20Ge 30Te 50 thin films deposited by vacuum evaporation on various substrates have been studied for their structural and optical properties. The as-deposited amorphous films were crystallized by thermally annealing them. The optical constants of the amorphous films indicate semiconducting behaviour ( n > k). The optical bandgap ( E g) determined from Tauc's plot is 0.7 eV. The change in reflectance on crystallization has been utilized to obtain maximum optical contrast by optimising the thickness of the film.