Thermally and photoinduced changes of structure and optical properties of As-Ga-S amorphous films and glasses

New high purity glasses in the As42S58-G(42)S(58) and A(40)S(60)-Ga40S60 sy stems were synthesised and the solubility regions of Ga42S58 and Ga40S60 in the As-S matrix were determined. Illumination of glassy powders and thin f ilms shifts the short wavelength absorption edge, changes the optical gap, E-g(opt), and changes their index of refraction, n. The sensitivity of Ga-c ontaining films is higher than pure As-S. Annealing and illumination also c hanges the thickness of thin films, their density, the single oscillator en ergy, E-0, dispersion energy, E-d, of the Wemple-DiDomenico dispersion rela tionship and their Raman spectra. The changes in the Raman spectra are inte rpreted as photoinduced changes of short-range order in the structure of th in films. A microscopic model of the photoinduced changes is proposed. (C) 1999 Elsevier Science S.A. All rights reserved.