The self-diffusion of Zn was measured in monocrystalline oxide samples by using non-radioactive 70Zn as a tracer, and secondary ion mass spectrometry for analysis. It was found that the diffusion coefficients (figure 4) were isotropic, and could be described at 850 to 1020C by:

D(m2/s) = 1.7 x 10-2exp[-3.85(eV)/kT]

The Zn self-diffusion was expected to be controlled by a vacancy mechanism.

Zinc Self-Diffusion, Electrical Properties and Defect Structure of Undoped Single Crystal Zinc Oxide. Tomlins, G.W., Routbort, J.L., Mason, T.O.: Journal of Applied Physics, 2000, 87[1], 117-23