Thermal stability of ion-implanted hydrogen in ZnO

The evolution of implanted H-2 profiles in single-crystal ZnO was examined as a function of annealing temperature (500-700 degreesC) by secondary ion mass spectrometry. The as-implanted profiles show a peak concentration of similar to2.7x10(19) cm(-3) at a depth of similar to0.96 mum for a dose of 10(15) cm(-2). Subsequent annealing causes outdiffusion of H-2 from the ZnO, with the remaining hydrogen decorating the residual implant damage. Only 0.2% of the original dose is retained after annealing at 600 degreesC. Rutherford backscattering/channeling of samples implanted with H-1 at a dose of 10(16) cm(-2) showed no change in backscattering yield near the ZnO surface, but did result in an increase near the end-of-range from 6.5% of the random level before H-1 implantation to similar to7.8% after implantation. Results of both cathodoluminescence and photoluminescence studies show that even for a H-1 dose of 10(15) cm(-2), the intensity of the near gap emission from ZnO is reduced more than 2 orders of magnitude from the values in unimplanted samples. This is due to the formation of effective nonradiative recombination centers associated with ion-beam-induced defects. (C) 2002 American Institute of Physics.