Theoretical Study Of The Structure,Stability And Electronic Properties On Boron Arsenide And Indium Arsenide Clusters

Low-dimension semiconductor materials of the III-V group is playing an important role in the fields, such as nano-optical electronics, molectron and nanodevice . For the past decades, theoretic and experimental study about the film, superlattice, nanotube and quantum dot of the III-V group semiconductor have achieved a great progress. However, by now, the investigation of boron arsenide and indium arsenide in 1 to 200 scope of the number of atoms is still very limited. Therefor, in this paper a study of the geometric, stability and electronic properties of boron arsenide and indium arsenide clusters, have been carried by density functional theory (DFT).First of all, the investigation of the lowest-energy structures, stabilities and electronic properties of BnAsn clusters (n=1-14) have been presented by means of the density-functional theory. The results show that the lowest-energy structures undergo a structural change from two-dimensional to three-dimensional when n=4. With the increase of the cluster size (n>4), the BnAsn clusters tend to adopt cage-like structures, which can be considered as being built from four-membered rings (4MRs) and six-membered rings(6MRs). B12As12, a fullerene-like cage with high symmetry, is the most stable cluster. The results of PDOS analysis reveal that a distinct spd hybrid can be found at the vicinity of Fermi level, and there are strong molecular and covalent characteristic in the clusters.Moreover, the effective core potential density functional calculations are performed to explore a series of InnAsn tubelike clusters up to n=90. It is interesting that all of the tubelike structures comply with some common properties, such as the general molecular structural formula Inpk/2Aspk/2 and the common structure units—the parallel polygons, 4MRs and 6MRs. Size-dependent cluster properties such as binding energy, HOMO-LUMO gaps, Mulliken charges on atoms and frontier molecular orbital surfaces have been discussed. The electron density distributions of HOMO and LUMO indicate that the chemical activity of the tubelike clusters at the two ends is stronger, which makes the clusters being conducive to grow longer. That is why we can get the tube-like clusters.Finally, based on the stable tube-like cluster structures, the same method have been employed to optimize the infinite InAs nanotubes (InAsNTs). Their atomic and electronic band structures are presented. The results show that one-dimensional InAsNTs can be prepared by proper assembly of tubelike clusters to form semiconductors with large band gap.The results of these studies are helpful for us to understand the growth of the structures and electronic properties of the boron arsenide clusters and indium arsenide nanotubes. Furthermore, they can present theoretical credible basis for the further experimental study of the low-dimension semiconductor materials of the III-V group.