A Number Of Semiconductor Nano Cluster Material Geometry And The Nature Of Theoretical Research

The discovery of C₆₀ molecule by Kroto et al in 1985 and subsequent synthesis of carbon nanotubes by Iijima in 1991 have opened new research opportunities in science, engineering, and technology. Since then, semiconductor clusters, in particular, based on silicon, carbon, boron, have been received much attention, for their novel qualities in electronics, optics, calorifics, even biology.In view of that more and more semiconductor clusters have been synthesized successfully, we can't obtain full information about the geometries and electronic qualities from the experiments, while theoretical methods become the most effective approach to study clusters. So in this paper, we study a series of semiconductor clusters containing silicon, carbon and boron in order to discover their ground state structures and the growth mechanisms as well as the building blocks, to design and predict the new clusters with certain special functional materials. On the other hand, we study the special qualities for larger nanocluster materials, such as carbon nanotubes (CNT) doped by B or Al atom as gas sensers in order to direct experiments.Now, we have obtained plentiful and substantial conclusions derived as follows:1. The present calculations not only indicate that silicon-carbon fullerenes are promised to be synthesized in future, but also provide a new way for stabilizing silicon cages by uniformly doping carbon atoms into silicon structures.It is well known that the fullerenes and nanotubes are generally concomitant with each other in the nature. In view of the fact that the SiC nanotubes have been synthesize successfully, (SiC)_n cages are expected to exist in a large family, similar to carbon fullerenes. So in the present work we proposed a series of silicon-carbon cagelike structures, (SiC)_n (n=6-36), based on the C and Si uniformly hybrid four- (4MRs) and six-membered rings (6MRs). As far as we known, this is the first study of SiC fullerenes. Their geometrical and electronic structures, as well as the relative stabilities were investigated systematically using the density functional theory. Our calculations indicate that all SiC cages proposed here present highly structural...