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Indexed by:期刊论文

Date of Publication:2008-02-19

Journal:VACUUM

Included Journals:SCIE

Volume:82

Issue:6

Page Number:664-667

ISSN No.:0042-207X

Key Words:ZnO; oxygen atmosphere; buffer layer; reflection high-energy electron diffraction; photoluminescence

Abstract:ZnO films were synthesized on Si(111) substrates by pulsed laser deposition (PLD) under four different growth conditions. The structural and optical properties of the samples were characterized by reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), and photoluminescence (PL) measurement. It is found that when ZnO film is directly prepared on Si, oxygen atmosphere can significantly enhance the near-band-edge (NBE) emission and decrease the deep-level (DL) emission, but cause a polycrystalline film. By introducing a homo-buffer layer fabricated at 500 degrees C in vacuum, epitaxial ZnO film with three-dimensional (3D) growth mode is achieved instead of the polycrystalline film. In particular, the epitaxial film with the buffer layer shows more intensive NBE emission and narrower full-width at half maximum (FWHM) of 98 meV than the film without the buffer layer. The experimental results suggest that both oxygen atmosphere and buffer layer are quite efficient during PLD to grow high-quality ZnO/Si heteroepitaxial films suitable for applications in optoelectronic devices. (c) 2007 Elsevier Ltd. All rights reserved.