Thermal Instability Of PbO-coated Pb Clusters And The Field-emission Properties Of The LECBD BN Cluster Films.

The properties and the dynamics of nanoclusters have been the research topics many years before and nowadays they, as nanoparticles, are the prominent members of the family of the new nanoobjects. Cluster beam technique is the most convenient method to produce cluster-assembled nanomaterial and it is the easiest and most precise-controlled one among all the nano-routes. My work is based on our cluster-beam deposition system (UHV-CBS) and it is about the new properties and dynamic of the cluster-assembled materials as listed in the following.The research of the thermodynamic process in PbO-coated Pb clusters (nanocells) and nanojet formation by heating such structures. By exposing the Pb clusters from LECBD method to air, we prepared the nanocells. When we heat them, the inner Pb core will melt and try to expand itself ahead of the outer shell. And then the pressure within the nanocells will increase with the heating temperature because the expansion is confined by the wall. The cell will be finally detonated with the burst-out of the core material. Such crack processes occurred as observed by TEM. The formation of star-shape nanounits (several sprouts) and the tadpole-shape nanounits (one sprout) were found in the TEM observation. Temperature-variable Raman scattering was carried out to monitor the pressure change in the heating process and it demonstrated the process stated above by the temperature-variable peak widths. The tadpole-shape one was finally attributed to the generation of liquid nanojet as predicted by U Landman and M. Moseler. We reported the first experiments of nanojet. Furthermore,...