Dynamics of Si plume produced by laser ablation in ambient inert gas and formation of Si nanoclusters

We have performed (1) time-resolved soft X-ray absorption measurements on a time scale up to 15 mu s after pulsed-laser ablation of silicon (Si) in an ambient Ar gas with a transient pressure of about 10 Torr and (?) investigation of the correlation between 1.6-eV photoluminescence (PL) from Si nanocluster-based films and the surface oxidation. No soft X-ray absorption lints corresponding to Si clusters were observed, indicating that it is likely that after 15 mu s, significant clustering takes place and then Si nanoclusters can prow. From experiments involving hydrogen termination and hydrogen atom treatment in addition to natural oxidation, it is found that the 1.6-eV PL originates from the interface of a Si nanocluster core and a surface oxide layer and occurs without hydrogen atoms. (C) 1998 Elsevier Science B.V.