It was found that self-organized nanostripe structures could form on the surface of ZnO(11•2) substrates upon annealing in air, and that high-quality semi-polar AlN could be grown onto such substrates by including a room-temperature epitaxial AlN buffer layer. The full-width at half-maximum value of the X-ray rocking curve for AlN 11•2 could be as low as 500arcsec. The observed tilt of the AlN(11•2) layer grown on ZnO(11•2) with self-organized nanostripes was lower than that on as-received ZnO(11•2); indicating that the nanostripe structure suppressed the introduction of misfit dislocations at the hetero-interface. This was attributed to the reduced stress-field around the nanostripes. The reduction in misfit dislocation density was thought to be responsible for the improvement in crystalline quality.

Improvement in the Crystalline Quality of Semipolar AlN(1102) Films by Using ZnO Substrates with Self-Organized Nanostripes. K.Ueno, A.Kobayashi, J.Ohta, H.Fujioka: Applied Physics Express, 2010, 3[4], 041002