Pulsed laser deposition technique was used for the fabrication of Ge-Te rich GeTe-Sb2Te3 (Ge6Sb2Te9, Ge8Sb2Te11, Ge10Sb2Te13, and 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, Ge10Sb2Te13, and Ge12Sb2Te15 layers.

Department of Graphic Arts and Photophysics Faculty of Chemical Technology University of Pardubice Studentská 573 53210 Pardubice Czech Republic

Equipe Verres et Céramiques UMR CNRS 6226 Sciences Chimiques de Rennes Université de Rennes 1 35042 Rennes Cedex France

Institut de Chimie de la Matière Condensée de Bordeaux CNRS 87 av du Dr Albert Schweitzer 33608 Pessac Cedex France

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