High-Density Saturation Effects of the Dislocations in n-Type Germanium

Abstract

The dislocation effects on electrical resistivity and Hall coefficient at the liquid-nitrogen temperature were examined in n-type germanium specimens whose dislocation density, distribution, and nature were determined by means of optical and electron microscopy. In particular, the high dislocation density regions were considered, where the space-charge cylinders and the low-mobility rings around the dislocations overlap. Three stages were revealed, the first connected with the bulk conductivity, the second with the conductivity in the low-mobility regions, the third with the prevalence of the minority hole conductivity. The interpretation of the experimental data led to the following determinations: the specific volumes of the space-charge cylinders and the low-mobility rings around the edge dislocations; the ratios between low mobility and bulk mobility of the electrons; the degree of the contamination specific of the deformations; the saturation hole concentrations and mobilities. Further, the availability of differentiated specimens with prevalence of either screw or edge dislocations made it possible to resolve the effects of the two types of dislocations.