Changing the composition of Ag–As–S amorphous films using photo-induced solid state reaction

• Published in: Journal of non-crystalline solids 2001-05, Vol.284 (1), p.168-173
• Main Authors: Wágner, T, Vlček, Mir, Kasap, S.O, Vlček, Mil, Frumar, M
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Disordered solids; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Glass transitions; Glasses; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Specific phase transitions; Structure of solids and liquids; crystallography
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/S0022-3093(01)00397-0

The technique of step-by-step optically-induced solid state reaction of Ag into As 33S 67 amorphous films, which has allowed the design of films with known silver concentrations, is reported. The host, As 33S 67 films, were photo-doped by consecutive dissolution of a 10 nm layer of silver, which resulted in a single layer film of optical quality as measured by optical transmissivity. The silver concentration of the samples ranged between 1 and 41 at.%. Such Ag containing films cannot be prepared directly by vacuum evaporation from AgAsS glasses due to the phase separation during evaporation process. We analyzed the affect of the silver doping in the host material on optical, thermal properties, and its structure by means of optical spectroscopy, temperature-modulated differential scanning calorimetry, and Raman spectroscopy, respectively. Optically-induced silver dissolution led to a formation of the solid solutions in above mentioned concentration range, connected with a decrease of –S–S– bonds due to their solid state reaction with migrating silver ions. The films with a silver content close to 25 at.% had the structure of stoichiometric AgAsS 2. There is evidence of As–As bond formation in photo-doped materials with a silver content >40 at.%. Results of all analytical techniques we used have helped to understand the processes taking place during silver photo-dissolution.