The results of charged deep-level transient spectroscopic measurements of undoped amorphous hydrogenated material were presented. The ability of the technique to resolve the gap-state distribution, and to monitor directly its changes after pre-equilibrium preparation by bias annealing, was demonstrated. Three groups of gap states were observed, with mean energies of 0.63, 0.82 and 1.25eV. Their energies, as well as the conditions which were required for their creation, were found to be in good agreement with the D+, D0 and D- states; according to an improved defect-pool model.

V.Nádazdy, R.Durný, E.Pincik: Physical Review Letters, 1997, 78[6], 1102-5