PHOTOCHEMICAL CONVERSION OF ELECTRICALLY CONDUCTIVE POLYSILANE FILMS INTO INSULATORS

Electrically conductive polysilane films doped with iodine can be conv erted into insulators to semiconductors by a photooxidation reaction. The conductivity can be controlled in the range 10(-15)-10(-4) S cm(-1 ) by regulation of the extent of the photooxidation reaction. Since th e nonirradiated area of the film keeps its doping susceptibility, it i s possible to prepare a conducting pattern on the film by a photolitho graphic technique. Network polysilanes containing various substituents , prepared by the disproportionation reaction of alkoxydisilanes, were primarily examined, in addition to polysilanes prepared by the Wurtz coupling reaction. UV and IR analyses indicated that the Si-Si bonds i n the polysilanes were changed into Si-O-Si bonds and Si-OH bonds by t he photooxidation.