GaN devices based on nanorods

D Cherns, L Meshi, I Griffiths, S Khongphetsak, S V Novikov, R P Campion, C T Foxon, Chaowang Liu, Philip Shields, Wang Wang

Research output: Contribution to journalArticlepeer-review

10 Citations (SciVal)


Transmission and scanning electron microscopy are used to examine the role of an intermediate nanorod layer in reducing threading defect densities in GaN/(0001)sapphire. Films grown by molecular beam epitaxy under N-rich conditions showed Ga-polar nanorods growing out of a more compact N-polar layer. The nanorods sometimes contained extended threading defects, which were faulted dipoles lying on {10-10} planes with a displacement vector of 1/2[0001], which act as sources for spiral growth. By overgrowing the nanorods under Ga-rich conditions, continuous epilayers were formed with threading defect densities down to 108 cm-2. In a second approach, nanorods produced by etching through a self-organised layer of Ni islands were overgrown by metal-organic chemical vapour deposition, to produce overlayers with defect densities down to 5*107 cm-2. In both cases, the mechanisms by which the nanorod layer reduces the threading defect density are identified.
Original languageEnglish
Article number012001
Number of pages10
JournalJournal of Physics: Conference Series
Issue number1
Publication statusPublished - 26 Feb 2010
Event16th International Conference on Microscopy of Semiconducting Materials
- University of Oxford, Oxford, UK United Kingdom
Duration: 17 Mar 200920 Mar 2009


  • threading defects
  • displacement vectors
  • Ga-rich conditions
  • self-organised
  • rich conditions
  • polar layers
  • overlayers
  • nanorod layers
  • metal-organic
  • spiral growth
  • chemical vapour deposition


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