Hot-filament assisted chemical vapor deposited amorphous hydrogenated material, with a low H concentration and a low defect density, was studied by means of 1H nuclear magnetic resonance techniques. It was demonstrated for the first time that H microstructures could be significantly altered in films of device-quality amorphous hydrogenated material. In the case of the present films, the existence of large H clusters accounted for 90% of the 2 to 3at% of H atoms. The remaining H was more widely dispersed, but was still aggregated within a small volume fraction of the material. The results suggested that an ideal amorphous hydrogenated network with a low defect density and high structural stability might not necessarily be homogeneous.

Y.Wu, J.T.Stephen, D.X.Han, J.M.Rutland, R.S.Crandall, A.H.Mahan: Physical Review Letters, 1996, 77[10], 2049-52