Influence of GaN polarity and intermediate-temperature buffer layers on strain relaxation and defects

C. X. Peng, H. M. Weng, C. F. Zhu, B. J. Ye, X. Y. Zhou, R. D. Han, W. K. Fong, C. Surya

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The dependence of strain relaxation and consequent generation defects on Gallium nitride (GaN) polarity and intermediate-temperature buffer layer (ITBL) has been observed by Raman scattering, photoluminescence (PL) and monoenergetic positron beam techniques. Raman scattering studies have indicated that tensile stress prefers and compress stress is present in N-polar and Ga-polar films, respectively. Furthermore, ITBL relaxes strains in Ga-polar GaN films more effectively than in N-polar GaN films. PL results show that peak shifts due to the effect of polarity and ITBL. Depth resolved defect-sensitive S parameter measurements, using monoenergetic positron beam, exhibit larger S parameter and shorter positron effective diffusion length in N-polar GaN samples than those in Ga-polar films. When ITBL is added, S parameter decreases and effective diffusion length increases in both groups. Hall mobility and carrier concentration measurement manifest a reduction of dislocation line and electrons trap centers such as VGa or Ga vacancy clusters.

Original languageEnglish
Pages (from-to)6-11
Number of pages6
JournalPhysica B: Condensed Matter
Volume391
Issue number1
DOIs
Publication statusPublished - Mar 15 2007
Externally publishedYes

Fingerprint

Strain relaxation
Gallium nitride
gallium nitrides
Buffer layers
polarity
Scattering parameters
Positrons
buffers
positrons
Defects
defects
diffusion length
Raman scattering
Photoluminescence
Raman spectra
photoluminescence
Hall mobility
Electron traps
Temperature
temperature

Keywords

  • Defects
  • GaN polarity
  • Strain

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Influence of GaN polarity and intermediate-temperature buffer layers on strain relaxation and defects. / Peng, C. X.; Weng, H. M.; Zhu, C. F.; Ye, B. J.; Zhou, X. Y.; Han, R. D.; Fong, W. K.; Surya, C.

In: Physica B: Condensed Matter, Vol. 391, No. 1, 15.03.2007, p. 6-11.

Research output: Contribution to journalArticle

Peng, C. X. ; Weng, H. M. ; Zhu, C. F. ; Ye, B. J. ; Zhou, X. Y. ; Han, R. D. ; Fong, W. K. ; Surya, C. / Influence of GaN polarity and intermediate-temperature buffer layers on strain relaxation and defects. In: Physica B: Condensed Matter. 2007 ; Vol. 391, No. 1. pp. 6-11.
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