Mobility-Lifetime Products in a-Si:H and the Dangling Bond Recombination Model

ABSTRACTFermi level and light intensity dependences of electron and hole lifetimes have been calculated using a recombination model which considers positively correlated dangling bonds as the only localized states in the gap. The model equations have been solved numerically taking into account the non-equilibrium statistics of correlated electrons and the Fermi level dependence of the defect density. The results are in agreement with the anticorrelated behavior of the majority' and minority carrier μτ products observed in a-Si:H. The majority carrier lifetime is found to be more sensitive to the photogeneration rate than the minority carrier lifetime. The position of the Fermi level with respect to the energies of the D° and D- centers in the gap is a determinant factor of the (°τ)e/(μτ)h ratio.