Optical characterization of bulk GaN grown by a Na-Ga melt technique

Brian Skromme, K. Palle, C. D. Poweleit, H. Yamane, M. Aoki, F. J. DiSalvo

Research output: Contribution to journalConference articlepeer-review

26 Scopus citations

Abstract

Colorless platelet and prismatic GaN crystals grown from a Na-Ga melt are characterized using room and low temperature photoluminescence (PL), reflectance, and micro-Raman scattering. The largest (∼ 3-4 mm) platelet shows a neutral donor-bound exciton (D0,X) PL peak with a full-width at half-maximum (FWHM) of 2.2 meV at 1.7 K. Raman scattering reveals an A1(LO) phonon mode in this sample at 739 cm-1, implying a free electron concentration (n) around 2-3 × 1017 cm-3. Smaller platelets grown in a pyrolytic BN crucible show even sharper exciton peaks, down to 0.22 meV FWHM. The stronger A1(LO) Raman peak lies at 733 cm-1 in this case, virtually unshifted by plasmon interactions. This observation implies n is in the mid 1016 cm-3 range or below. Residual Zn acceptors are frequently observed, and two-electron transitions identify the binding energy of the residual donor species as 33.6 meV, which may be ON. The 2.2 eV yellow PL band is generally weak or absent. The high purity and excellent optical properties may be due to gettering of donors such as O by the Na in the melt.

Original languageEnglish (US)
Pages (from-to)299-306
Number of pages8
JournalJournal of Crystal Growth
Volume246
Issue number3-4
DOIs
StatePublished - Dec 16 2002
EventBNS 2002 - Amazonas, Brazil
Duration: May 18 2002May 23 2002

Keywords

  • A1. Impurities
  • A1. Optical characterization
  • A2. Growth from solutions
  • A2. Single crystal growth
  • B1. Nitrides
  • B2. Semiconducting III-V materials

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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