Crystal orientation mechanism of ZnTe epilayers formed on different orientations of sapphire substrates by molecular beam epitaxy

Journal Article · Tue Oct 28 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4900739· OSTI ID:22308150

Yamashita, S.; Aiba, T.; Hattori, S.; Sun, W.; Taguri, K.; Kazami, F. ^[1]; Kobayashi, M. ^[1]

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1. Department of Electrical Engineering and Bioscience, Waseda University, Tokyo 169-8555 (Japan)

The electrooptic effect in ZnTe has recently attracted research attention, and various device structures using ZnTe have been explored. For application to practical terahertz wave detector devices based on ZnTe thin films, sapphire substrates are preferred because they enable the optical path alignment to be simplified. ZnTe/sapphire heterostructures were focused upon, and ZnTe epilayers were prepared on highly mismatched sapphire substrates by molecular beam epitaxy. Epitaxial relationships between the ZnTe thin films and the sapphire substrates with their various orientations were investigated using an X-ray diffraction pole figure method. (0001) c-plane, (1-102) r-plane, (1-100) m-plane, and (11-20) a-plane oriented sapphire substrates were used in this study. The epitaxial relationship between ZnTe and c-plane sapphire was found to be (111) ZnTe//(0001) sapphire with an in-plane orientation relationship of [−211] ZnTe//[1-100] sapphire. It was found that the (211)-plane ZnTe layer was grown on the m-plane of the sapphire substrates, and the (100)-plane ZnTe layer was grown on the r-plane sapphire. When the sapphire substrates were inclined from the c-plane towards the m-axis direction, the orientation of the ZnTe thin films was then tilted from the (111)-plane to the (211)-plane. The c-plane of the sapphire substrates governs the formation of the (111) ZnTe domain and the ZnTe epilayer orientation. These crystallographic features were also related to the atom arrangements of ZnTe and sapphire.

• OSTI ID: 22308150
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 16 Vol. 116; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTALLOGRAPHY
CRYSTALS
EQUIPMENT
LAYERS
MOLECULAR BEAM EPITAXY
ORIENTATION
SAPPHIRE
SUBSTRATES
THIN FILMS
X-RAY DIFFRACTION
ZINC TELLURIDES