Electrical and Optical Properties of Highly Non-stoichiometric GaAs

The studies of transport and optical properties of GaAs implanted with high arsenic doses were performed. As-implanted samples showed hopping conductivity and the exponential absorption tail in the near-IR region. Both effects were probably caused by the amorphization of implanted layer. Using EPR measurements it was found that arsenic antisite defect with high local strain field was created during implantation. Annealing of implanted layers at 600°C led to substantial removal of amorphization, decrease in absorption coefficient and hopping conductivity leading to resistive samples. The possible model of such behaviour may be similar to the one of suggested for low temperature GaAs layers.