Cathodoluminescence as a method for the study of degradation of polysilanes

The paper presents a unique cathodoluminescent (CL) method suitable for studying polysilane properties and the first CL characteristics of the material being investigated. Poly[methyl(phenyl)silylene] (PMPSi) was selected as a typical representative of polysilanes. The PMPSi study is based on the measurement of the intensity of CL emission after passing through the specimen. The major problem of this study is the susceptibility of the material being investigated to the degradation by electron beam. PMPSi degradation strongly decreases the CL intensity. Therefore, detection in the synchronous mode was used to eliminate the influence of the background and of the noise. It was found that the degradation process is partly reversible. A partial recovery of intensity was attributed to reverse recombination reactions of silyl radicals in a vacuum after 20 h of annealing at room temperature. Understanding of the physical and chemical mechanisms of the degradation and of the reversible process of the PMPSi CL emission is interesting for science as well as the application (e.g. resist in electron beam lithography or molecular scale electronic devices).