Abstract
The application of an optical bias excitation during decay after pulsed excitation allows detailed study of the kinetics of tunnelling recombination and dispersive transport. Experimental results are reported that show that, at low temperature, the decay curve of the high energy (1·4eV) photoluminescence band of a-Si:H integrated over energy is independent of bias up to a cut-off time, in full agreement with the theory of tunnelling recombination. The value of the cut-off provides a measurement of the carrier density. Similar results are obtained at higher temperatures. These data can also be interpreted in terms of the multiple trapping model if hopping among the localized states is included.