Defects and defect behaviour in GaAs grown at low temperature

We have performed a systematic study of GaAs layers grown at low temperature against the growth temperature and annealing treatments using x-ray diffraction, IR absorption, Hall effect, electron diffraction and Auger spectroscopies. The correlation between the observations obtained with these techniques allowed us to correctly measure the excess As concentration and to show that As antisite related defects can account for all the As in excess. We demonstrate that these As antisites related defects contain two As atoms and we propose a specific model for this defect which explains its disappearance at a relatively low temperature.