Epitaxial Growth of ZnO Films on (0001) Sapphire at Low Temperatures by Electron Cyclotron Resonance-assisted Molecular Beam Epitaxy and Their Microstructural Characterizations

Publisher Website
Google Scholar
Abstract
The details of epitaxial growth and microstructural characteristics of ZnO films grown on (0001) sapphire were investigated using X-ray diffraction (XRD), reflection high energy electron diffraction (RHEED), and plan-view and cross-sectional transmission electron microscopy (TEM). The films were grown by electron cyclotron resonance-assisted molecular beam epitaxy (ECR-assisted MBE). The ECR-assisted MBE was found to be capable of growing high quality epitaxial ZnO films at low temperatures in comparison with chemical vapor deposition (CVD) and RF sputtering. The films exhibited a high degree of epitaxy, a sharp interface between film and substrate, and a smooth surface morphology. The TEM observations revealed that the films were epitaxial with an orientational relationship of (0001)ZnO ∥(0001)Al_2O_3 and [1̄21̄0]ZnO ∥[1̄100] Al_2O_3. This is equivalent to a 30° rotation of ZnO relative to sapphire in (0001) plane.