Atomic scattering spectroscopy for determination of the polarity of semipolar AlN grown on ZnO

摘要

Determination of the polarity of insulating semipolar AlN layers was achieved via atomic scattering spectroscopy. The back scattering of neutralized He atoms on AlN surfaces revealed the atomic alignment of the topmost layers of semipolar AlN and the ZnO substrate. Pole figures of the scattering intensity were used to readily determine the polarity of these wurtzite-type semipolar materials. In addition, we found that +R-plane AlN epitaxially grows on —R-plane ZnO, indicating that the polarity flips at the semipolar AlN/ZnO interface. This polarity nipping is possibly explained by the appearance of -c and m-faces on the —R ZnO surfaces, which was also revealed by atomic scattering spectroscopy.