Minority-carrier injection and extraction inn-type germanium

A new injection effect predicted by a previous reexamination of the transport equations has been experimentally confirmed by probe measurements on near-intrinsic $n$-type germanium at low forward-current densities. It implies an increase of local effective resistivity due to the difference in carrier mobility between electrons and holes. At high current densities, the familiar resistivity decrease is observed, and the changeover from one operating regime to the other occurs at current densities which are in good agreement with calculations. An analogous extraction effect for reverse currents is also documented. It leads eventually to total minority-carrier depletion within a substantial bulk region.