Point-contact measurements for high-resolution profiling of high-resistivity III - V semiconductors

A point-contact technique operating at low forward bias was used for high-resolution profiling of semi-insulating GaAs and InP as well as of medium-resistivity undoped n-type GaAs. Electrical mesoscopic non-uniformities strongly correlated to the cellular structure of dislocations could be detected in LEC GaAs and VGF GaAs. Between the profiles of the point-contact current and of the band - band photoluminescence intensity a close correlation was observed on nearly all LEC GaAs samples and on InP. In the case of VGF GaAs, on the contrary, an anticorrelation exists.