International audienceThin films of amorphous alumina were fabricated using pulsed laser deposition. Topography, structural, and optical properties of alumina films were investigated depending on process parameters, specifically deposition time under vacuum and partial pressure of argon. Deposited films present good uniformity with RMS roughness ranging from 0.35 to 2.50 nm. Alumina films with thickness lower than 40 nm deposited under vacuum present a non-negligible void content that induces a decrease of the effective refractive index of the layers. Furthermore, introduction of argon gas (at 5×10−4 and 5×10−2 mbar) during the deposition process induces grainy structure of the thin films documented by an increase of RMS roughness from 0.35 to 1.5 nm. A decrease of the alumina layers’ refractive index is observed in the 300–7500 nm spectral range when increasing Ar pressur

Amorphous Ge–Sb–Se thin films were fabricated by a rf‐magnetron co‐sputtering technique employing the following cathodes: GeSe2, Sb2Se3, and Ge28Sb12Se60. The influence of the composition, determined by energy‐dispersive X‐ray spectroscopy, on the optical properties was studied. Optical properties were analyzed based on variable angle spectroscopic ellipsometry and UV‐Vis‐NIR spectrophotometry. The results show that the optical bandgap range 1.35‐2.08 eV with corresponding refractive index ranging from 3.33 to 2.36 can be reliably covered. Furthermore, morphological and topographical properties of selenide‐sputtered films studied by scanning electron microscopy and atomic force microscopy showed a good quality of fabricated films. In addition, structure of the films was controlled using Raman scattering spectroscopy. Finally, irreversible photoinduced changes by means of change in optical bandgap energy and refractive index of co‐sputtered films were studied revealing the photobleaching effect in Ge‐rich films when irradiated by near‐bandgap light under Ar atmosphere. The photobleaching effect tends to decrease with increasing antimony content.