The tailoring of the composition of Ag-As-S amorphous films using photo-induced solid state reaction between Ag and As30S70 films

Kinetics of optically induced reaction between silver and As30S70 films was measured by monitoring the change in thickness of the undoped chalcogenide using a modified computer-controlled reflectivity technique. Silver concen tration profiles during optically induced solid state reaction (OSSR) were traced by means of Rutherford backscattering spectroscopy (RBS). The compos ition of the As-S films was chosen to be As30S70, which is the most favorab le for optically induced solid state reaction, because it yields a homogene ous photodoped product. A new technique of step-by-step optically induced s olid state reaction of Ag into As30S70, amorphous films, which has allowed to design films with exact silver concentration and to study their properti es, is reported. The host As30S70 films were photodoped by consecutively di ssolving a thin (similar to 20 nm) layer of silver, which resulted in homog eneous films of good optical quality. The silver concentration of the films ranged between 1 and 27 at.%. We have analyzed in detail the influence of the silver doping in the host material on optical and thermal properties, a nd its structure. The photodoped films produced a single-phase homogeneous material with its structure close to AgAsS2 in some of them. Results of all analytical techniques have helped to understand the processes taking place during silver photodissolution. (C) 2001 Elsevier Science B.V. All rights reserved.