Rapid preparation of highly ordered ultraflat ZnO surfaces

We report a simple procedure for preparing atomically flat and microscopically well ordered ZnO single crystal surfaces of various orientations which consists of an initial cleaning step by ion sputtering, followed by subsequent annealing in air. The resulting atomic ordering and morphology have been validated for both polar basal planes as well as the mixed terminated (image) surface by means of low energy electron diffraction (LEED) and atomic force microscopy (AFM) and were further compared with other preparation schemes. It is demonstrated that this procedure allows a very rapid and reliable preparation of unreconstructed surfaces with extended terraces whose size is limited by the precision of the macroscopic sample orientation.