Structural information from the Raman spectrum of amorphous silicon

The Raman scattering from various model structures for amorphous silicon is computed. It is shown that the width of the ``optic peak'' increases roughly linearly with the rms bond-angle distortion {Δ}θb of the network. The experimentally observed linewidths lead to 7.7^∘{}{≤}{Δ}θb{≤}10.5^∘{}. The smaller linewidths (and hence angles) correspond to networks that have been annealed at higher temperatures. These results are consistent with model-building experience which shows that it is impossible to construct fully bonded amorphous networks with {Δ}θb{≤}6.6^∘{}.