The time-dependent diffusion constant, D = Do(t)-, of H in radio-frequency sputter-deposited hydrogenated amorphous films which contained 3 to 5at% of Si-bonded H, was found to increase with time at temperatures of between 300 and 380C. That is, the dispersion parameter, , was negative. As in previous studies,  generally decreased with temperature up to a sample-dependent temperature, and then increased at higher temperatures.

R.Shinar, J.Shinar, H.Jia, X.L.Wu: Physical Review B, 1993, 47[15], 9361-5