Growth and characterization of periodically polarity-inverted ZnO structures on sapphire substrates

We report on the fabrication and characterization of periodically polarity inverted (PPI) ZnO heterostructures on (0 0 0 1) Al2O3 substrates. For the periodically inverted array of ZnO polarity, CrN and Cr2O3 polarity selection buffer layers are used for the Zn- and O-polar ZnO films, respectively. The change of polarity and period in fabricated ZnO structures is evaluated by diffraction patterns and polarity sensitive piezo-response microscopy. Finally, PPI ZnO structures with subnanometer scale period are demonstrated by using holographic lithography and regrowth techniques.