Structure of Amorphous Silicon and Silicon Hydrides

Neutron scattering measurements have been made on pure, hydrogenated, and deuterated samples of amorphous silicon ($a$-Si) in the wave-vector range 0.007-8.75 ${\mathrm{\AA }}^{-1\mathrm{}}$. Small-angle data indicate structures in the samples of average radius of gyration as large as 270 Å. Large-angle data show that for the concentrations we have measured (14%), the structure of $a$-Si is not altered by the incorporation of large amounts of H or D. The silicon-hydrogen and silicon-deuterium partial structure factors have also been obtained.