Surface morphology of [11-20] a-plane GaN growth by MOCVD on [1-102] r-plane sapphire
MOCVD生长的[ 1-102]r面蓝宝石衬底上的[11-20 ]a面GaN表面形貌研究

Nonpolara-plane 11-20] GaN has been grown onr-plane 1-102] sapphire by MOCVD, and investigated by high resolution X-ray diffraction and atomic force microscopy. As opposed to thec-direction, this particular orientation is non-polar, and it avoids polarization charge, the associated screening charge and the consequent band bending. Both low-temperature GaN buffer and high-temperature AlN buffer are used fora-plane GaN growth on r-plane sapphire, and the triangular pits and pleat morphology come forth with different buffers, the possible reasons for which are discussed. The triangular and pleat direction are also investigated. A novel modulate buffer is used for a-plane GaN growth onr-plane sapphire, and with this technique, the crystal quality has been greatly improved.