On the optical properties of amorphous Ge–Ga–Se films prepared by pulsed laser deposition

Abstract Amorphous Ge–Ga–Se thin films (pure and dysprosium doped) were prepared by the pulsed laser deposition technique using different energy of the laser beam pulses. The effects of exposure and thermal annealing below the glass transition temperature on the optical parameters (index of refraction, optical band gap) and the thickness of as-deposited chalcogenide thin films were studied. The optical band gap and the thickness of the thin films increased with exposure of the films and even more with the annealing. Index of refraction has an opposite tendency. Two emission bands with maxima near 1140 and 1340 nm corresponding to 6F9/2, 6H7/2–6H15/2 and 6F11/2, 6H9/2–6H15/2 electron transitions of Dy3+ ions were identified in luminescence spectra of dysprosium doped thin films.