Wurtzite-type ZnO is the polar crystal whose (0001) surface is terminated by Zn ions. The surface structure of ZnO single crystal was investigated by Atomic Force Microscope (AFM), Reflection High-Energy Electron Diffraction (RHEED) method and Coaxial Impact-Collision Ion Scattering Spectroscopy (CAICISS). From AFM observations, the surface had a step/terrace structure and the step height was evaluated as a half of a lattice parameter. In order to remove impurities adsorbed on the surfaces, the samples were heated in an analysis chamber at 900°C for 3 hours under a pressure of 5×10-7 Pa with the irradiation of oxygen radical, and CAICISS and RHEED were observed. It was shown from RHEED patterns that the surface had (1 X 1) structure. From the polar angle dependence of CAICISS-TOF spectra for Zn ions, a peak due to the focusing effect for the 1st to 5th layer of Zn ions was observed at about 2° higher angle than a simulated angle. It could be concluded that the uppermost Zn ions were moved outside of the surface by 7% due to the relaxation.
|ジャーナル||Key Engineering Materials|
|出版ステータス||Published - 2000 1月 1|
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