Glass Formation and Properties of Chalcogenide Systems

Abstract

Glass-forming regions of ternary Ge-Te-Cu and Ge-Te-In chalcogenide glasses are examined by differential scanning calorimetry and by X-ray diffraction. Glass transition and crystallization temperatures are about 120 °C To 260 °C, relatively higher than those of binary Cie-Te glass [11]. Only a small range of compositions after quenching the melting alloy is characterized by disorder state, but this range of composition is widened when using a vapor deposition technique. These compositions have two glass transition temperatures, showing the existence of different phases in the sample. Both Kissinger equation and modified Kissinger Kinetic analysis were adopted to estimate the activation energy and the reaction order of the process. Ge-Te-Cu and Ge-Te-In crystallized in two stages, nucleation and crystal growth. These two processes can be distinguished by exothermal crystallization patterns. Art atomic radial distribution analysis has been made on bulk Ge1Te4Inx and Ge1Te4Cu. with x=0.1 by X-ray diffraction techniques. The radial distribution function (RDF) is discussed in terms of the structure factor F(s). Thin films of Ge-Te-Cu and Ge-Te-In are deposited on silicate glass and silicon wafer substrates by vacuum evaporation. The optical energies Eopt are determined from the transmission andreflection data of deposited films. The value of E00 decreased by increasing metal additive such as Cu or In and discussed as a function of the conditions of their preparation such as substrate type.