LXXXVII. Theory of dislocations in germanium

Abstract

Abstract Dislocations have a large effect on the electrical properties of germanium. Experiments show that dislocations act as acceptor centres. This paper discusses a simple model (due to W. Shockley) which identifies dislocation acceptors with the dangling unpaired electrons on the edge of the extra atomic plane of a dislocation having some edge component. In n-type germanium the line of acceptors along a dislocation accepts electrons and becomes negatively charged. The electrostatic energy in the resulting space charge region is found and shown to be a dominant factor in determining the occupation of dislocation acceptors. Formulas are given for the temperature variation of the average electron concentration in n-type material that has been lightly deformed by plastic bending. Experiments are suggested to test the theory and determine exactly the energy level of the dislocation acceptors.