Effect of energy deposition on the disordering kinetics in dual-ion beam irradiated single-crystalline GaAs

The damage induced in GaAs crystals irradiated with dual-ion beam (low-energy I2+ and high-energy Fe9+), producing simultaneous nuclear (Sn) and electronic (Se) energy depositions, was investigated using several characterization techniques. Analysis of the damage buildup shows that Sn alone (single 900 keV ion beam) leads, in a two-step process, to full amorphization of the irradiated layer (at a fluence of 1.5 nm−2) and to the development of a high (2.2%) elastic strain. Conversely, only one step in the disordering process is observed upon dual-ion beam irradiation (i.e., 900 keV I2+ and 27 MeV Fe9+, Sn&Se); hence, amorphization is prevented and the elastic strain remains very weak (below 0.2%). These results provide a strong evidence that, in GaAs, the electronic energy deposition can induce an efficient dynamic annealing of the damage created in collision cascades formed during nuclear energy deposition.