Structural properties of CrN buffers for GaN growth

W. H. Lee, I. H. Im, T. Minegishi, Takashi Hanada, M. W. Cho, T. Yao, D. C. Oh, C. S. Han, K. W. Koo, J. J. Kim, O. Sakata, K. Sumitani, S. J. Cho, H. Y. Lee, S. K. Hong, S. T. Kim

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

We have investigated the structural properties of CrN layers grown on (0001) Al2O3 substrates by molecular-beam epitaxy. The CrN layers of high-crystal quality are obtained at a low growth temperature of 500 °C. X-ray diffraction studies indicate that the CrN layers grow along the 〈111〉 direction with a cubic structure. In-situ reflection high-energy electron diffraction investigations clarify that the CrN layers have the following epitaxy relationship with the Al2O3 substrates: 〈121〉 of (111) cubic CrN // 〈11-20〉 of (0001) corundum Al2O3 and 〈101〉 of (111) cubic CrN // 〈1-100〉 of (0001) corundum Al2O3. Based on the above results, the mismatch of the in-plane lattice spacing between the CrN layers and the Al2O3 substrates is evaluated to be around 6.6%. When the CrN layers are used as the buffer layers for GaN growth, the GaN layers grown on the CrN layers show well-resolved excitonic emission lines in the photoluminescence spectra, whereas the GaN layers grown without the CrN layers exhibit a broad near-band-edge emission. It is suggested that CrN buffers are effective in relieving the lattice mismatch between Al2O 3 substrates and GaN layers.

Original languageEnglish
Pages (from-to)928-933
Number of pages6
JournalJournal of the Korean Physical Society
Volume49
Issue number3
Publication statusPublished - 2006 Sep 1

Keywords

  • Buffer
  • CrN
  • GaN
  • Molecular-beam epitaxy

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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