Photostability of pulsed-laser-deposited As_xTe_100-x (x=40, 50, 60) amorphous thin films.

As_xTe_100-x amorphous thin films were fabricated by a pulsed laser deposition technique with the aim of finding photostable layers in as-deposited but preferably in relaxed (annealed) state. Photostability was studied in terms of the films' stability of refractive index and bandgap under near-bandgap light irradiation. As₄₀Te₆₀ and As₅₀Te₅₀ layers were found to be photostable in both as-deposited as well as relaxed states. Moreover, As₅₀Te₅₀ layers present the lowest surface roughness. These characteristics make pulsed-laser-deposited As₅₀Te₅₀ thin films promising for applications in nonlinear optics.