Diffusion length measurements in p-HgCdTe using laser beam induced current

The minority carrier diffusion length in p-HgCdTe is a key indicator of material quality and gives an indication of n-on-p diode performance when the zero bias resistance is diffusion limited. We present results of a temperature dependent study of diffusion length in p-HgCdTe using laser beam induced current (LBIC). Carriers are collected by a p-n junction formed using standard diode junction formation conditions, and thus not necessarily extending to the substrate. Two-dimensional modeling is used to examine the validity of results obtained using this geometry, as compared to the more standard diffusion length test structure geometries, which are harder to fabricate. The temperature dependence of the diffusion length can be compared with theoretical models to determine the dominant recombination mechanisms.