Study of transport, trapping and recombination mechanisms in microcrystalline silicon by transient photoconductivity

Abstract We have studied different sets of microcrystalline silicon films deposited by PECVD and plasma assisted HWCVD at different thicknesses and microstructures. Measurements by time-resolved microwave conductivity (TRMC) give a mobility μ TRMC , diffusion-induced mobility μ DTRMC and field effect mobility μ FE . At high carrier density, the dependence of the TRMC signal on carrier density is sublinear, with slope γ , indicating dominance of shallow trap recombinations. The decay of the signal shows two slopes τ 1 and τ 2 . From the analysis of μ TRMC , μ DTRMC , μ FE , γ , τ 1 and τ 2 for different samples, we discuss the contribution of grains, grain boundaries, and column boundaries to the mobility, to the fast recombination process, and to the lifetime.