A review was presented of recent measurements of trap-dominated H diffusion in disordered Si. The H transport could be described by a model with 3 levels: a transport level, shallow traps and deep traps. At low concentrations, diffusion was dominated by deep traps which were well separated in energy from shallow traps. At high H concentrations, the trap density ranged from 8 x 1019 to 1021/cm3, and increased approximately as the square root of the H concentration. Moreover, H diffusion depended upon the carrier concentration and doping level as well as upon the H concentration. It was concluded that muon spectroscopy should be able to provide previously unavailable information concerning transport levels, shallow traps and the effects of carriers upon H motion in shallow traps.

W.B.Jackson: Philosophical Transactions of the Royal Society A, 1995, 350[1693], 237-48