The microstructure of nonpolar GaN layers grown on r-plane sapphire substrates was investigated using transmission electron microscopy (TEM). The structure of the GaN layers was predominantly a-plane oriented single-crystal. In the a-plane oriented layers, misoriented grains about 200 nm in size with a preferential orientation were detected by selecting a proper observation direction. The preferential orientation relationship between the a-plane oriented layers and the misoriented grains was analyzed using atomic structure models, and two possible formation mechanisms of the misoriented grains were suggested.
- A1. Characterization
- A1. Defects
- A3. Hydride vapor phase epitaxy
- B1. Nitrides
- B2. Semiconducting IIIV materials