Orientational Relationships and Atomic Arrangements of GaN Nanorods Grown on Al2O3 (0001) Substrates by Using Hydride Vapor Phase Epitaxy

Abstract

Scanning electron microscopy (SEM) images and transmission electron microscopy (TEM) images showed that the one-dimensional GaN nanorods were formed on Al2O3 (0001) substrates by using hydride vapor phase epitaxy without a catalyst. Selected area electron diffraction (SAED) pattern and high-resolution TEM (HRTEM) results showed that GaN nanorods grown on Al2O3 (0001) substrates had crystalline wurzite structures and (0001) preferential orientation. The morphologies of GaN nanorods were affected by the flow rates of the source materials. The orientational relationships between the GaN nanorods and the Al2O3 substrates were (0001)(GaN)parallel to(0001)Al2O3 and [01 (1) over bar0](GaN)parallel to[11 (2) over bar0](Al2O3). Cross-sectional and plan-view atomic arrangements of the fully relaxed interfacial region are described on the basis of the TEM, the SAED pattern, and the HRTEM results.