Electronic properties of dislocation structures in elemental semiconductors

A new, general model explaining the electronic properties of dislocation structures in elemental semiconductors is presented. The model is inferred from phenomena observed in Ge and Si crystals with edge-type dislocations are analysed in terms if two types of states: local states resulting from the strain field in the distorted regions of dislocations, and states analogous to those in the amorphous semiconductors occurring in the highly disordered (amorphous) regions of dislocations. In both n- and p-type Ge the Fermi level in the amorphous regions is fixed about 0.45 eV below the conduction band edge. The experimental results of electron paramagnetic resonance, optical absorption, radiative recombination and photoconductivity in plastically deformed crystals are taken into consideration and explained in terms of the proposed model.