Hydrogen incorporation depths of more than 25µm were obtained in bulk monocrystalline samples during exposure to 2H plasmas for 0.5h at 300C. This produced an estimated diffusivity of about 8 x 10–10cm2/Vs at that temperature. The activation energy for diffusion was 0.17eV; thus indicating an interstitial mechanism. Subsequent annealing at 500 to 600C was sufficient to evolve all of the H; at least within the sensitivity of secondary ion mass spectrometry (below 5 x 1015/cm3). The thermal stability of H retention was slightly greater when the H was incorporated by direct implantation relative to plasma exposure, due to trapping at residual damage in the former case.
Hydrogen Incorporation and Diffusivity in Plasma-Exposed bulk ZnO. Ip, K., Overberg, M.E., Heo, Y.W., Norton, D.P., Pearton, S.J., Stutz, C.E., Luo, B., Ren, F., Look, D.C., Zavada, J.M.: Applied Physics Letters, 2003, 82[3], 385-7