Density of states in the gap of microcrystalline silicon determined from thermally-stimulated currents

This paper presents the determination of the density of states (DOS) in the energy gap from the Fermi level towards the conduction band edge in microcrystalline silicon (mu c-Si:H) from experimental and numerically simulated thermally-stimulated currents (TSC). The simulation is based on the numerical solution of the rate equations and takes recombination, thermal emission and trapping into account. A combined experiment-simulation approach allowed to provide the evidence of the strong and weak retrapping regimes. In this approach different simulations have been performed in order to reproduce the experimental TSC and then to get the DOS from which the band tail parameter is deduced. (C) 2007 Elsevier B.V. All rights reserved.