Formation of gas atom encapsulated silicon clusters using electron beam generated silicon plasmas

Nano-sized silicon (Si) clusters are formed using a Si plasma generated by an electron beam gun in the absence of an additional rare-gas plasma. In the case that an argon (Ar) plasma is superimposed on the Si plasma, on the other hand, not only the pure Si clusters but also Ar-doped Si clusters are found to be produced according to the analysis using a laser-desorption time-of-flight mass spectrometer. In addition, it is detected by an X-ray photoemission spectroscope that the doped Si clusters are mainly composed of Si and Ar. Based on these results, structure of the Si clusters is considered to be a spherical shape containing the Ar atom at the center of the Si cage. When a krypton (Kr) plasma is included in the Si plasma, however, it is revealed that Kr is difficult to be encapsulated into the Si clusters, which is attributed to its larger atomic-size compared with Ar.