Structural order and clustering in annealedα−SiCandα−SiC:H

Abstract

We carried out a theoretical investigation of the structural properties of annealed $\ensuremath{\alpha}\ensuremath{-}\mathrm{SiC}$ and $\ensuremath{\alpha}\ensuremath{-}\mathrm{S}\mathrm{i}\mathrm{C}:\mathrm{H}.$ The calculations were performed using the free volume Monte Carlo method combined with interatomic potentials. Our prototype nanoparticle contained as much as 85 000 atoms which allows for a superior statistical sampling of the material. The results show that C atoms segregate, forming small clusters embedded in an extensive Si network. Si atoms are mostly contained in a single extensive network and a few small clusters. Unprecedented detailed ring statistics analysis shows that C clusters do not form strictly C rings and that the introduction of H increases the occurrence of microvoids in the structure. Moreover, the incorporation of H slightly reduces the chemical order in the material and, to a larger extent, reduces the midrange structural order. Hydrogen also relaxes bonding stress around atoms in the network. The results are consistent with the available experimental data.