Photoluminescence study of chloride VPE-grown GaN

Tetsuzo Ueda, Masaaki Yuri, Heon Lee, James S. Harris, Takaaki Baba

Research output: Contribution to journalConference article

1 Citation (Scopus)

Abstract

We have examined the effect of growth conditions on photoluminescence (PL) characteristics of chloride VPE-grown GaN films. Undoped GaN films are grown on sapphire by a newly developed chloride VPE system which utilizes GaCl3 and NH3 as source materials. We find that the spectra depend strongly on the growth temperatures and the corresponding surface morphology. Peaks from excitons and donor-acceptor pairs (D-A pair) recombination are observed for the films with terrace-like flat surfaces grown at between 950°C and 1000°C. A peak due to exciton bound to neutral donors is observed for a growth temperature of 975°C where the acceptor-related peaks are not seen. Decreasing the growth temperature below 950°C causes rough surfaces due to three-dimensional growth, whereas increasing the growth temperature above 1000°C causes cracks or partial pealing off of the film. The films with rough surfaces or crystal failures show broad emission from deep acceptor levels. As a result, residual acceptors are eliminated in the very narrow range of the growth temperature around 975°C. It is also noted that an increase of the V/III ratio during the growth makes the line width of the band-edge peak narrower. The PL results show that a growth temperature around 975°C and high V/III ratio are essential to obtain better crystal quality and reduced concentration of residual acceptors.

Original languageEnglish
Pages (from-to)189-194
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume421
DOIs
Publication statusPublished - 1996
EventProceedings of the 1996 MRS Spring Meeting - San Francisco, CA, USA
Duration: 1996 Apr 81996 Apr 12

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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