Light-enhanced reactivation of donors in hydrogenatedn-type GaAs

The donors in undoped and S-doped GaAs are passivated by exposure to a hydrogen plasma. The influence of laser illumination (1.54 eV) on the reactivation of the passivated donors at 100 ^∘{}C is investigated. It is found that the dissociation of the donor-hydrogen complex is greatly enhanced under illumination. The reactivation of the passivated donors follows an initially fast process, which for long annealing times reduces to a reactivation process obeying second-order kinetics. The rate-limiting process is explained in terms of the combination of two hydrogen atoms into a molecular species.