THE ROLE OF GA ANTISITE DEFECT IN THE ACTIVATION PROCESS OF TRANSMUTED IMPURITIES IN NEUTRON-TRANSMUTATION-DOPED SEMI-INSULATING GAAS

In neutron-transmutation doping for undoped and In-doped GaAs irradiated with thermal and fast neutrons of 1.5×1018 and 7.0×1017 cm-2, we have found for the first time photoluminescence emissions around 860 and 935 nm at 77 K associated with the two difference levels of Ga antisite defect (Ga As). It is suggested that the annealing of GaAs defects plays an important role in the activation process of transmuted impurities as well as the annealing of As antisite defects forming midgap electron traps. The GaAs defects are annihilated in an annealing temperature range from 650 to 700°C, accompanied by an abrupt decrease in resistivity.