Conductivity of Grain Boundaries in Grown Germanium Bicrystals

The conduction of current in the grain boundary of a grown germanium bicrystal has been studied as a function of doping. For all samples, the behavior shows only a small temperature dependence from 2-300°K. The conduction in the grain boundary is ohmic if no secondary effects are introduced by conduction in the bulk material. Samples with no doping and with $n$-type, $p$-type, or copper doping are all characterized by having a resistivity of about 3000 to 11 000 ohms per square. The lack of a strong dependence on doping indicates that the grain boundary behavior is not due to the segregation of impurities at the boundary.