A contactless photoconductance technique for the identification of impact ionization

A new, contactless, microwave photoconductance based technique for the direct measurement of the spectral dependence of free carrier generation efficiency in semiconductors is described and demonstrated. The technique is applied to the search for hetero-junction assisted impact ionization (HAII) with promising initial results. A strong photo-dielectric effect is also revealed for a ZnS:i-Si interface demonstrating the ability of the technique to characterize results other than the enhanced photoconductivity we seek. Such characterization will help to inform the next step in hetero-junction preparation.