Electronic structures of c -plane and a -plane AlN/ZnO heterointerfaces determined by synchrotron radiation photoemission spectroscopy

J. W. Liu, A. Kobayashi, K. Ueno, S. Toyoda, A. Kikuchi, J. Ohta, H. Fujioka, H. Kumigashira, M. Oshima

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12 Citations (Scopus)

Abstract

c -plane and a -plane AlN films have been grown on single-crystal ZnO substrates by pulsed laser deposition at room temperature. The electronic structures of c -plane and a -plane AlN/ZnO heterojunctions have been characterized by synchrotron radiation photoemission spectroscopy. Based on the binding energies of core-levels and valence-band maximum values, the valence-band offsets have been found to be 0.4±0.1 and 0.1±0.1 eV for the c -plane and a -plane AlN/ZnO heterojunctions, respectively. Both heterojunctions show type-II band configurations with conduction band offsets of 3.0±0.1 and 2.7±0.1 eV, respectively. The potential on the ZnO side bends downward toward the interface for the a -plane AlN/ZnO heterojunction. However, that bends upward toward the interface for the c -plane AlN/ZnO heterojunction. This phenomenon is explained well by the effect of spontaneous polarization in AlN and ZnO.

Original languageEnglish
Article number252111
JournalApplied Physics Letters
Volume97
Issue number25
DOIs
Publication statusPublished - 2010 Dec 20
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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