Structure and energy level calculations of dislocations in gallium arsenide

Abstract

The geometry of dislocations in the sphalerite structure is described and illustrated. Particular attention is given to the dissociated set of dislocations. Calculations of the energy levels of the 30° and 90° glide partials are made using a tight-binding Hamiltonian and a supercell containing a pair of dislocations of opposite sign. Two sets of parameters describing the Hamiltonian are used. Several models of the core structure of each partial are analysed. The results suggest that, at low temperature, core reconstructions occur leading to full bands separated from empty ones. These conclusions are compared with experimental results based on electrical, photo-conductivity, and particularly, velocity measurements on doped plastically deformed gallium arsenide. In general, the agreement between the theoretical results and experiments is satisfactory.