Core-hole photoionization study of polysilane compounds

We present the results obtained with a new experimental set-up designed for the study of free semi-conductor clusters. This set-up is aimed to study the mass distribution of particles and the evolution of electronic properties as a function of the size, using the technique of core hole photoionization. The cluster production is based on the technique of radio-frequency discharge decomposition of a gas. We study the gaseous particles (Si _n H _x , 0<x<2n+2) generated by pure silane (SiH₄) discharges at low pressures (<10 millitorr) under continuous RF (Radio-Frequency) excitation conditions. We have studied the neutral species present in the post discharge zone and the positive ions present in the discharge. We identify the neutral species as polysilane compounds. We have also compared the ionization spectra obtained near Si-2p edge for the particles containing few silicon atoms with the spectra of SiH₄ and Si₂H₆ molecules. For these molecules, the experimental observations are in agreement with theoretical calculations.