Investigation of oxygen and other impurities and their effect on the transparency of a Na flux grown GaN crystal

Mohammed Abo Alreesh, Paul Von Dollen, Thomas F. Malkowski, Tom Mates, Hamad Albrithen, Steven DenBaars, Shuji Nakamura, James S. Speck

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

In this study, we investigate several impurities in bulk GaN crystals grown by the sodium flux technique. In our system, black GaN is in general associated with oxygen, sodium, and molybdenum concentrations in excess of 1019 atoms/cm3. Here, we report on the correlation of high levels of oxygen with opaque crystals. Samples that contain oxygen concentrations above 1019 atoms/cm3 are highly absorbing regardless of the presence of other impurities. Experiments with partially submerged seeds indicated material grown mainly above the nominal liquid surface was more transparent and had a generally lower impurity concentration, especially oxygen. In optically transparent regions, concentrations of oxygen, sodium, and carbon were as low as 7 × 1016, 2 × 1016, and 5 × 1016 atoms/cm3, respectively, while the concentration of molybdenum was below the detection limit.
Original languageEnglish (US)
Pages (from-to)50-57
Number of pages8
JournalJournal of Crystal Growth
Volume508
DOIs
StatePublished - Jan 3 2019
Externally publishedYes

ASJC Scopus subject areas

  • Materials Chemistry
  • Inorganic Chemistry
  • Condensed Matter Physics

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