Generation of argon-ion mixed silicon plasmas forming argon encapsulated silicon clusters

An inductively coupled argon (Ar) plasma is superimposed on a silicon (Si) plasma generated by an electron beam gun in order to realize the formation of gas-atom encapsulated Si cage clusters. The Si clusters, which are formed and deposited on a substrate, are analyzed by laser-desorption time-of-flight mass spectrometry and are found to have the mass spectra of not only pure Si cluster (Sin; n=1-17) but also Si cluster doped with Ar atom (ArSin; n=10-20) in the case that the large amount of Ar ions is generated in addition to the Si plasma. Together with the analysis of x-ray photoelectron spectroscopy, it is revealed that the Ar atom is included in the Si cluster, forming the structure of endohedral Ar at Sin complexes. Furthermore, the mass spectrum of Ar at Sin indicates the existence of the magic numbered cluster size n=15, 16 similar to the metal encapsulated Si clusters