Sequential Reactions of Silicon Clusters with Silanes: Constrained Heterogeneous Nucleation of Hydrogenated Silicon Particles

The sequential clustering reactions of gas phase silicon cluster ions are ideally suited for studying heterogeneous nucleation of silicon particles. Stepwise reactions of silicon cluster ions with silanes have been observed which lead to growth of larger hydrogenated silicon clusters. Direct laser evaporation of bulk silicon just outside the ion cell of a Fourier transform mass spectrometer produces abundant positive and negative silicon cluster ions. Double resonance ejection is used to eliminate all but a single cluster mass.