The Structure of Amorphous Hydrogenated Silicon:Carbon Alloys Using X-Ray and Neutron Scattering and Computer Simulation - The Effect of Hydrogen Dilution

Abstract

Neutron and X-ray diffraction techniques have been applied to the study of two samples of a-Si:C:H. Both samples were prepared using conventional glow discharge methods, but the hydrocarbon/silane precursor gas was diluted with hydrogen in one case. Analysis of the X-ray diffraction data gives a clear picture of the silicon network, since the scattering profile is dominated by the Si-Si correlations. The high real-space resolution neutron diffraction data, however allows one to comment on the effect of this dilution on the silicon-carbon bonding morphology, and in particular on the degree to which the additional hydrogen enhances hetero-coordination. In addition we present the results of a preliminary computer simulation study of the structure of a-C:H and a-Si:H using an approximate molecular dynamic density functional theory, and discuss its viability in the study of the more complex a-Si:C:H ternary alloy.