Metastable rocksalt ZnO interfacial layer and its influence on polarity selection of Zn-polar ZnO films

• Published in: Journal of crystal growth Vol. 312; no. 2; pp. 263 - 266
• Main Authors: Yuan, H.T., Liu, Y.Z., Mei, Z.X., Zeng, Z.Q., Guo, Y., Du, X.L., Jia, J.F., Zhang, Z., Xue, Q.K.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2010; Elsevier
• Subjects: A1. Interface; A1. Metastable structure; A1. Phase equilibrium; A1. Planar defects; A3. Molecular beam epitaxy; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron diffraction and scattering; Exact sciences and technology; Low-energy electron diffraction (leed) and reflection high-energy electron diffraction (rheed); Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; 68.37.Lp; A1. Phase equilibrium; 68.35.Ct; 68.35.Rh; A1. Interface; A3. Molecular beam epitaxy; A1. Metastable structure; 61.14.Hg; A1. Planar defects; Metastable states; Plasma assisted processing; RHEED; Phase transitions; Structural models; Thin films; Molecular beam epitaxy; Phase equilibria; Chemical bonds; Zinc oxide; Polarity; Crystal structure; Buffer layer; Epitaxial layers; Stacking sequence; Magnesium oxide; Theoretical study; Template reaction; Plane defects; Lattice parameters; Interfaces; Transmission electron microscopy; Atomic models; Growth mechanism; Wurtzite structure
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2009.10.054

By a metastable rocksalt ZnO interfacial structure and a resulting rocksalt-to-wurtzite structure transition in ZnO buffer layer, polarity control of Zn-polar ZnO films was realized on rocksalt MgO (1
1
1) template by plasma-assisted molecular beam epitaxy. The metastable rocksalt ZnO and the phase transition from octahedrally bonded rocksalt to tetrahedrally bonded wurtzite structure during the growth of ZnO buffer layer were established by the combination of
in situ reflection high-energy electron diffraction and
ex situ high-resolution transmission electron microscopy. Such a metastable rocksalt ZnO has a lattice constant
a=4.16
Å and a typical …
abcabc… atom stacking along the growth direction. Polarity selection of Zn-polar ZnO films was found greatly depending on the bonding configuration of the epitaxial ZnO interfacial layer, and an atomic model of the structure transition was proposed to explain the mechanism of ZnO polarity selection.