Effects of annealing on the surface structure of Ga‐isotope‐implanted single‐crystal ZnO

We studied the effects of Ga isotope implantation on surface structure using single‐crystal (0001) ZnO with an atomically flat surface. The surface morphology with steps and terraces was greatly changed by Ga implantation and post‐annealing: the step‐and‐terrace structure was suppressed by Ga implantation but a step‐and‐terrace structure appeared on the surface after post‐annealing at 900 °C for 4 min. The diffusion of Ga towards the surface through dislocation pipes at a density of up to 5 × 10 8 cm −2 was the dominant mechanism, and a significant amount of Ga moved from the implanted layer to the surface. The reaction between Ga and ZnO during post‐annealing appeared to improve sheet resistance and surface morphology. Copyright © 2005 John Wiley & Sons, Ltd.