| Chalcogenide glasses form a structurally interesting and technologically useful class of materials. They have potential applications as semiconductors, low-frequency waveguides or solid state electrolytes. They possess medium range order as determined from numerous experimental studies, thus making structurally rich materials. Traditionally these glasses are synthesized by thermally quenching a high temperature melt formed from the elements. Compositionally, in the phosphorus-sulfur and the silicon-sulfur systems for example, the glass formation regions are well defined leaving little room for structural or compositional modification. This constraint points to the need for investigating nontraditional methods of synthesis if new materials are to be developed. The research presented here is the first application of plasma enhanced chemical vapor deposition (PECVD) to the synthesis of materials in the phosphorus-sulfur and the silicon-sulfur systems. The precursors used in the PECVD synthesis are hydrogen sulfide, silane, and trimethylphosphine. The PECVD materials are characterized primarily by solid state NMR and Raman spectroscopies. In the silicon-sulfur system, unlike the bulk glasses where the site speciation is fixed and phase separation is a problem at higher sulfur contents, the ratio of corner to edge sharing SiS... |
