Using nanoindentation and cathodoluminescence to identify the bundled effect of gallium nitride grown by PA-MBE

Hua Chiang Wen, Wu Ching Chou, Tun Yuan Chiang, Yeau-Ren Jeng, Wen Chung Fan

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We performed cathodoluminescence (CL) investigations on GaN NCs grown using molecular beam epitaxy. Bundled GaN was used to form NCs that were deposited onto commercial sapphire templates. The structures of the bundled NCs were analyzed using nanoindentation. The samples were grown with a TGof 700, 800, and 850 °C, and the H values were 7.4 ± 0.2 and 6.4 ± 0.2 GPa; the E values were 308.4 ± 4.3, 296.4 ± 3.8, and 75.5 ± 1.4 GPa, respectively. It is suspected that the discrepancies of the mechanical parameters obtained by various indentation methods are partially a result of the stress distribution inherent in the different orientations on the sapphire substrate. A scanning electron microscopy (SEM) system equipped with CL allows the direct comparison of SEM images and CL maps, captured from exactly the same area of the samples. In addition to the SEM and CL images, photoluminescence spectroscopy (PL) profiling was obtained by collecting the 20 K PL spectra at the samples. The PL profiling enables the distinguishing of the emissions by the 5 meV of the blueshift from 3.440 to 3.445 eV due to localization effects. The bundled GaN NCs resulted from the (0002) reflection at 34.6° for a wurtzite structure and a raised intensity difference when the TGwas increased from 700 to 850 °C. The crystal texture of the GaN can influence the mechanical properties at different TGstages.

Original languageEnglish
Pages (from-to)615-621
Number of pages7
JournalJournal of Alloys and Compounds
Volume693
DOIs
Publication statusPublished - 2017 Jan 1

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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