Films doped with Al were deposited with a pulsed laser deposition technique to characterize the charge compensation phenomena in ZnO. In particular, O radical (O*) irradiation during film deposition was used to modify the O stoichiometry. Irradiation with O* decreased electron concentration in Al-doped ZnO. The lattice parameter of the resultant films also varied with the growth conditions. However, no obvious correlation between electron concentration and lattice parameter was found. The self-diffusion coefficients indicated the presence of non-equilibrium defects. The properties of the films were considered from the viewpoint of non-equilibrium compensated defects detected in the diffusion measurements.

Non-Equilibrium Defects in Aluminum-Doped Zinc Oxide Thin Films Grown with a Pulsed Laser Deposition Method. Ryoken, H., Sakaguchi, I., Ohashi, N., Sekiguchi, T., Hishita, S., Haneda, H.: Journal of Materials Research, 2005, 20[10], 2866-72