Thermal annealed, transient annealed, and pulsed laser annealed, n-type ion implanted samples of Cr-doped and undoped semi-insulated GaAs will be investigated by the method of deep level transient spectroscopy (DLTS) and other relevant electrical and optical measurements. GaAs samples with light and heavy doping of Si and Se will be examined. Capless thermal annealing will be performed in the annealing furnace, transient annealing (1 - 10 sec) will be employed for the encapsulated samples, and laser annealing will be done by using dye and XeCl excimer laser. Profiles of deep energy levels will be studied by DLTS and C-V measurements to determine the redistribution of impurities and defects during the thermal treatment.
