The sign of charge carriers in luminescent transitions

A thorough treatment of the luminescent mechanisms in high resistivity semiconductors (up to 10¹² ohm cm), has as yet not been satisfactorily established. This is due to the lack of data as is provided by the Hall effect. An AC-AC Hall apparatus has been assembled to determine the sign of charge carriers, and their densities when involved in luminescent transitions. Results of preliminary measurements on CdS will be presented.We would like to thank J. Hickmott for his assistance in designing and assembling the synchronous detector filter system.