Recombination via discrete defect levels with application to semiconductor material characterisation

Semiconductor material characterization in terms of defect parameters is presently evaluated experimentally by applying the Shockley-Read-Hall (SRH) recombination time constant expression. A recent analytic solution to the SRH rate equations extended to differential rate equations for two multiple defect level systems, yields a solution derived without an approximation. In terms of material characterisation, this exact solution is shown to provide detailed information on multiple level depths in contrast to the existing theory, which relies on one dominant single level. Furthermore, for semiconductor samples known to be predominantly doped with one defect species, it is shown theoretically that the dominant decay is influenced by the other defect species present in the semiconductor sample.