Geometries and Vibrational Spectra of Small Hydrogenated Silicon Clusters

Abstract

We report a systematic study of ground state structures, vibrational spectra, cohesive energies and HOMO-LUMO gaps of small SinH clusters (n = 3, 10) based on the nonorthogonal tight-binding molecular dynamics scheme. The ground state structures have been obtained by using simulated annealing. In particular, we focus on how the addition of a hydrogen atom affects the ground state geometry and the stability of a Sin cluster. We find that hydrogen either enters into the surface of the cluster or occupies a position outside the cluster. In the first case, it drastically distorts the cluster, while in the latter, there is very little distortion. We find that in some cases SinH cluster has some resemblance with Si n+1 cluster. We also find that hydrogen can form bonds with more than one silicon atom. Our calculation indicates that SiH, Si 3 H and Si 5 H will be more stable and Si 4 H, Si 6 H, Si 7 H, Si 9 H and Si 10 H will be less stable clusters.

Tight-binding calculations of Si-H clusters using genetic algorithms and related techniques: Studies using differential evolution

“…qualitatively similar to what was obtained by SGA and SA, [5,19,20] by some quarks of computing, the DE predicted the cohesive energy as Ϫ7.04 eV, as opposed to the Ϫ12.87 A total of 12 clusters were calculated during this study. between 0.0001 and 0.2 and the crossover probability between 0.5 and 0.99, and decided not to proceed further.…”

“…3 The ground state structure of Si 2 H 2 cluster determined as Ϫ6.56 eV, that is, very similar to the values obtained in earlier calculations. [5,19,20] Although the cohesive energy calculated through DE is actually identical to what was obtained earlier through SGA, [5] the bond lengths are now slightly altered. Here, the two Si-H bond lengths are calculated as 1.62 and 2.12 Å , respectively, as against 1.51 and 2.71 Å calculated through SGA.…”

“…[19,20] for studying covalently bonded material. It assumes that the system consists of ionic cores and electron gas and tends to calculate the total energy functional for the entire system…”

“…The calculated value of cohesive energy is 10.14 eV, which is in excellent agreement with the earlier work. [19,20] The DE was able to resolve this structure approximately were necessary to resolve a structure, and, often, the computawithin 500 generations, and, in fact, a near-optimal situation tion for larger assemblages took a lesser amount of time was reached much earlier. A variable mutation constant compared to some of the smaller assemblages.…”

Study of growth of dot and column in porous silicon samples of various thicknesses prepared at a constant current density

“…Several oxygen modified defect states have been identified experimentally on PS as SiO 2 [10], NBOHC (nonbridging oxygen hole center) interfacial defects in SiO 2 /Si [11,12] or surface bound oxy-hybrids. According to Chang et al [13] the luminescence properties of ambient aged PS are associated with SiO x .…”