Formation Mechanism of {0001} ZnO Epitaxial Layer on γ-LiAlO2(100) Substrate by Chemical Vapor Deposition

The formation mechanism of {0001} oriented ZnO epitaxial film on gamma-LiAlO2 (100) substrate was studied by x-ray diffraction and electron microscopy. At a relatively low temperature of 575 C, kinetics and possibly low surface energy allowed the {0001} oriented ZnO to nucleate on LiAlO2 subsequent to the formation of the {10 (1) over bar0} oriented ones, which is favored from a thermodynamic point of view. The {0001} oriented ZnO islands had a high growth rate and overgrew the {10 (1) over bar0} oriented islands to form a continuous epilayer. Because a large portion of the substrate surface was masked by the {10 (1) over bar0} oriented crystals, the laterally overgrown portion of the {0001} oriented crystals possessed a low density of dislocations and therefore good light-emitting characteristics. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3515319] All rights reserved.