Abstract Non-polar (1 1 2¯ 0) GaN has been successfully grown on (0 0 1) LaAlO 3 (LAO) substrate by pulsed laser deposition method. The nitrogen plasma is essential to grow pure a -plane GaN films. The insertion of a ZnO buffer layer improves the quality of GaN thin film as shown by X-ray diffraction. Reflection high energy electron diffraction and cross-sectional transmission electron microscopy with selected area diffraction reveal two types of a -plane GaN domains perpendicular to each other in orientation relationships of [0 0 0 1] GaN ∥[1 1¯ 0] LAO and [1 1¯ 00] GaN ∥[1 1¯ 0] LAO .