Defects and interfaces in an epitaxial ZnO/LiTaO3 heterostructure

S. H. Lim, D. Shindo

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

ZnO films were grown on a (0112) r-plane LiTaO3 substrate by electron cyclotron resonance-assisted molecular-beam epitaxy. The detailed structures of the interface and defects are investigated by high-resolution electron microscopy and image simulation. The epitaxial relationship was found to be [0001]ZnO||[0111]LiTaO3 and (1120)ZnO||(0112)LiTaO3. This epitaxial relationship corresponds to the c axis of ZnO parallel to the piezoelectric r-plane LiTaO3, which results in the enhanced electromechanical coupling factor. The interfaces were very smooth and structurally semicoherent with a comparative regular array of misfit dislocations at the interface accommodating a lattice mismatch of 9.49% when the incident electron beam is parallel to the [0001]ZnO||[0111]LiTaO3 direction. A high efficiency of transfer of acoustic energy across the interface is expected for surface acoustic wave devices with such an interface. The dominant defects commonly observed in ZnO films were found to be the type-I1 intrinsic stacking fault. The formation of stacking faults was shown to be growth kinetics on particular crystallographic planes during the initial stage of film growth. The effects of these defects and interfaces on electrical and optical properties for device applications are discussed.

Original languageEnglish
Pages (from-to)5107-5112
Number of pages6
JournalJournal of Applied Physics
Volume88
Issue number9
DOIs
Publication statusPublished - 2000 Nov 1

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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