Recombination Lifetimes in a-Si:H/a-SiC:H Multilayers

Abstract

ABSTRACTThe recombination processes in a-Si:H and a-Si:H/a-SiCo.3s:H multilayers at T=10 K are studied by transient photoluminescence on a time scale from 2 ns to 100 ms. Our investigations yield a lifetime distribution with two peaks at ∼1 ms and ∼1 /μS for bulk a-Si:H. We present measurements on samples with varying defect density ND. It is shown that there is no significant shift of the two lifetimes as a function of ND. However, the relative contribution of the μs-peak is enhanced with increasing ND. In a-Si:H/a-SiC:H multilayers with a varying number of interfaces and well layer thicknesses dsi there is also no discernible change of the lifetimes as a function of the overall defect density. An additional peak at ∼20 ns is observed for samples with dsi smaller than ∼30 Å. It may be attributed to recombination in the interface layers.