Atomistic simulation of semiconductor nanostructures by O(N) TBMD method

The atomistic properties of nano-scale semiconductors, are studied using the tight-binding molecular-dynamics (TBMD) method. We focus our attention on the atomic reconstruction and the defects in the nano-scale crystallites and investigate their influences on the properties of the nanostructure materials. This TB theory, with only three adjustable parameters gives values of the energies and bonding distances which are in excellent agreement with the ab initio results for small semiconductor clusters. We apply the TBMD scheme far the calculations of lattice defects (dislocations) and gamma-surface in the small semiconductor crystallites with the size of N less than or equal to 1000. We have found that there are marked differences in the properties of lattice defects between those in the bulk and those in the nano-scale semiconductor crystallites. The similar calculations are also also performed for the nano-scale metallic systems, and qualitatively different behaviors, compared to those of the semiconductor crystallites, have been found.