Near-surface structure of polar ZnO surfaces prepared by pulsed laser deposition

Polarity-controlled homoepitaxial ZnO films were prepared in order to investigate the near-surface and the electronic structures of ZnO films with Zn-polar (0001) and O-polar 0001¯ surfaces. Neutral atom scattering spectroscopy revealed that the near surface atomic structure and the polarity of the single crystal substrate with a step and terrace structure was maintained even at the surface of the epitaxial films through substrate-mediated growth without a defect structure. X-ray photoelectron spectroscopy study also revealed that the surfaces of ZnO films and single crystal substrates showed similar band bending regardless of the surface polarity. The state of surface band bending is discussed and compared with other reports regarding ZnO and GaN.