Nuclear magnetic resonance 1H dipolar echo measurements were performed on B-doped, P-doped, compensated and intrinsic samples of amorphous hydrogenated material. It was found that, at room temperature, the dipolar spin lattice relaxation time was related to the macroscopic diffusion constants which were determined by means of secondary ion mass spectroscopy measurements. The local jump frequencies which were deduced from these values of the spin lattice relaxation time were orders of magnitude higher than those values which were deduced from macroscopic diffusion results. Also, the associated activation energies were much lower (about 0.2eV). At 150 and 100K, the dipolar echo in samples which contained 0.001P exhibited both a narrow line and a broad line. The full widths at half-maximum of the narrow line and the broad line were the same as those of the narrow and broad components of the free induction decay, respectively. Because the narrow line exhibited a spin lattice relaxation time with a slightly different temperature dependence to that of the spin lattice relaxation time for the broad line, the local motion was slightly different for H atoms in the clustered and dilute phases.

P.Hari, P.C.Taylor, R.A.Street: Journal of Non-Crystalline Solids, 1993, 164-166[1], 313-6