Determination of the recombination rate constants in amorphous silicon from double-injection experiments

Abstract

Abstract An investigation of recombination kinetics in a-Si p+-i-n+ junctions and similar specimens with lightly doped central regions, is reported. All samples were prepared by the glow-discharge technique. Using reverse bias, steady electron and hole saturation currents were injected into the specimen from opposite sides using highly absorbed light from two independent sources. The interaction of the primary electron and hole currents is shown to lead to a ′current loss′ associated with carrier recombination. The analysis of the room-temperature results is based on a simple kinetic model involving multi-trapping transport of the excess carriers and interaction with the D0, D+ and D− states of the dangling-bond centre. A consistent set of rate constants and cross-sections is deduced for trapping and recombination transitions into the above states. It is concluded that for recombination paths through both the D+ and D− states, the hole transition represents the limiting rate and this is discussed in relation to hole transport in a-Si.