Pulsed laser deposition technique was used for the fabrication of Ge-Te rich GeTe-Sb₂Te₃(Ge₆Sb₂Te₉, Ge₈Sb₂Te₁₁, Ge₁₀Sb₂Te₁₃and Ge₁₂Sb₂Te₁₅) amorphous thin films. To evaluate the influence of GeTe content in the deposited films on physico-chemical properties of the GST materials, scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffraction and reflectometry, atomic force microscopy, Raman scattering spectroscopy, optical reflectivity and sheet resistance temperature dependences as well as variable angle spectroscopic ellipsometry measurements were used to characterize as-deposited (amorphous) and annealed (crystalline) layers. Upon crystallization, optical functions and electrical resistance of the films change drastically, leading to large optical and electrical contrast between amorphous and crystalline phases. Large changes of optical/electrical properties are accompanied by the variations of thickness, density and roughness of the films due to crystallization. Reflectivity contrast as high as ~0.21 at 405 nm was calculated for Ge₈Sb₂Te₁₁, Ge₁₀Sb₂Te₁₃and Ge₁₂Sb₂Te₁₅layers.

The detection of molecules dissolved in liquid medium can be envisaged by means of an optical integrated sensor operating in middle infrared range. The intended sensor is composed of a cladding and a guiding selenide sputtered layers transparent in middle infrared. Hence, Ge-Sb-Se thin films were selected in view of tailored refractive index contrast, successfully deposited by radio frequency magnetron sputtering and characterized. To maximize the evanescent field at a wavelength of 7.7 µm, a suitable selenide waveguide allowing measuring the optical transmitted power was designed by performing computer simulations based on the effective index method enabling single-mode propagation for a waveguide width between 8 and 12 µm. Selenide sputtered films were micro-patterned using reactive ion etching with inductively coupled plasma process. Finally, optical waveguide surface was functionalized by the deposition of a hydrophobic polymer, which will permit detection of organic molecules in water.

Ge-Sb-Te thin films were obtained by ns-, ps-, and fs-pulsed laser deposition (PLD) in various experimental conditions. The thickness of the samples was influenced by the Nd-YAG laser wavelength, fluence, target-to-substrate distance, and deposition time. The topography and chemical analysis results showed that the films deposited by ns-PLD revealed droplets on the surface together with a decreased Te concentration and Sb over-stoichiometry. Thin films with improved surface roughness and chemical compositions close to nominal values were deposited by ps- and fs-PLD. The X-ray diffraction and Raman spectroscopy results showed that the samples obtained with ns pulses were partially crystallized while the lower fluences used in ps- and fs-PLD led to amorphous depositions. The optical parameters of the ns-PLD samples were correlated to their structural properties.