Tight‐binding molecular dynamics simulation of SiH bond dissociation in silicon clusters

Abstract

ABSTRACT:New model of SiOH bond dissociation is proposed and tested in the cluster Si 10 H 16 by the simulation approach that combines classic molecular dynamics method and the self-consistent tight-binding electronic and total energy calculation one. It is shown that the monohydride SiOH bond is unstable with respect to silicon dangling bond and bend-bridge SiOHOSi bond formation when this cluster traps the single positive charge and that hydrogen migrates through a path involving rather rotation around the SiOSi bond than the center of this bond (the bond-centered position). These results can be useful for understanding hydrogen-related phenomena at surfaces, interfaces, and internal voids of various hydrogenated silicon systems: electronic devices, silicon solar cells, and nanocrystalline and porous silicon.

Sodium effects on the electronic and structural properties of porous silicon for energy storage

“…As can be seen, in the pSi H the bond length Si–H is 1.51 ± 0.006 Å, while the bond length Si–Si is 2.39 ± 0.03 Å. Both distances are in agreement with previous theoretical reports of passivated small silicon clusters 89‐93 . A comparison of the radial distribution functions of both substitution types with the pSi H function shows that the main modifications occur on the probability density of the Si–H bonds; as these regions decrease in size and have displacements above 1.52 Å and up to 1.58 Å in the case of the highest concentration of substitutional Na atoms on the walls.…”

“…Both distances are in agreement with previous theoretical reports of passivated small silicon clusters. [89][90][91][92][93] 93 A comparison of the radial distribution functions of both substitution types with the pSi H function shows that the main modifications occur on the probability density of the Si-H bonds; as these regions decrease in size and have displacements above 1.52 Å and up to 1.58 Å in the case of the highest concentration of substitutional Na atoms on the walls. This result was expected in both substitution cases since Na adsorption is carried out through some H atoms, and therefore only a few Si-H bonds are elongated to keep the Na atoms in equilibrium.…”

Chemical manipulation of multifunctional hydrocarbons on silicon surfaces

“…However, a unit that is often used in theoretical investigations of the hydrogen-terminated Si (111) substrate, the Si 10 H 16 cluster with the structure of adamantane, has been a subject of recent theoretical investigations [49][50][51][52][53][54][55][56][57] with a successful synthesis of methyl-terminated Si 10 H 16 cluster reported by Fischer et al [58]. The selective synthesis of silicon clusters of specific structure is currently rare.…”

Thermochemical Property Estimation of Hydrogenated Silicon Clusters

“…For structure calculations and insights into the reactivity of very large clusters, i.e., sizes greater than 15–30 silicon atoms up to 6400 silicon atoms, semiempirical methods, ab initio molecular dynamics, and/or genetic algorithm with tight binding (GA/TB) approaches have been used. ,− These methods are used (1) due to very long supercomputing times using very accurate quantum chemical composite methods such as G3//B3LYP or CBS-QB3 and (2) due to the difficulty and inefficiency in finding the global minimum in structure through manual manipulation. There is interest in larger clusters and their reactivity (e.g., hydrogen dissociation from hydrogenated silicon clusters), and thermochemical data for larger clusters is greatly needed to gain insight into the reaction kinetics through existing kinetic correlations. − It is well-established that hydrogenated silicon nanostructures pass through metastable configurations (or transient chemical species) before reaching a global minimum from molecular dynamics simulations, but detailed knowledge of the structure and thermochemistry of a wide range of hydrogenated silicon clusters is still needed.…”