PROPERTIES OF SILICON-TIN ALLOYS PREPARED BY PULSED-LASER DEPOSITION

Metastable thin-film alloys of tin and silicon have been grown on room temperature substrates by pulsed laser deposition. The composition of the targets, made by pressing pellets of a mixture of tin and silicon powders, was maintained in the deposited films. The granular films co nsisted of tin nano-crystallites surrounded by an amorphous matrix. De posited films with tin concentration greater than 15% showed metallic behavior, optically as well as electrically, while films with tin cont ents less than 15% displayed optical bandgaps ranging from 100 to 300 meV. Charge transport in the semiconducting films can be modeled by a combination of conduction in extended states and hopping at the Fermi level. (C) 1995 American Institute of Physics.