Structural analysis of InGaN epilayers

K.P. O'Donnell, J.F.W. Mosselmans, R.W. Martin, S. Pereira, M.E. White

Research output: Contribution to journalArticle

92 Citations (Scopus)

Abstract

The structural properties of InGaN have attracted interest on account of the recent widespread use of the material in visible light-emitting devices. A key topic has been the indirect determination of the composition by x-ray diffraction (XRD). We examine critically the several levels of approximation involved in this procedure. It is shown by extended x-ray absorption fine structure (EXAFS) measurements that the local structure of InGaN is independent of the composition, in the range of InN fraction, from about 15 to 40%, that corresponds to blue to infrared light emission from this material. EXAFSdetermined ratios of the numbers of indium and gallium atoms in the first metal co-ordination shell, M1, show very good agreement with the composition measured by established techniques, both structural and chemical, on similar samples. On the other hand, the atomic separations deviate markedly from values calculated using Vegard's law. In particular, the average radial separations, In-N1 = 2.11(2) î.. and In-M1 = 3.28(3) î.., do not vary significantly with In/Ga ratio in the examined composition range. We conclude with some brief comments on the uncertain but challenging topic of InGaN nanostructure.
LanguageEnglish
Pages6977-6991
Number of pages14
JournalJournal of Physics: Condensed Matter
Volume13
Issue number32
DOIs
Publication statusPublished - 13 Aug 2001

Fingerprint

Epilayers
structural analysis
Structural analysis
Chemical analysis
X rays
Gallium
Indium
Light emission
x ray absorption
gallium
light emission
indium
Structural properties
Nanostructures
x ray diffraction
Diffraction
Metals
fine structure
Infrared radiation
Atoms

Keywords

  • InGaN
  • light-emitting devices
  • x-ray diffraction
  • nanoscience

Cite this

O'Donnell, K.P. ; Mosselmans, J.F.W. ; Martin, R.W. ; Pereira, S. ; White, M.E. / Structural analysis of InGaN epilayers. In: Journal of Physics: Condensed Matter. 2001 ; Vol. 13, No. 32. pp. 6977-6991.
@article{d04afd8ab85b48aebb33857587b04ac5,
title = "Structural analysis of InGaN epilayers",
abstract = "The structural properties of InGaN have attracted interest on account of the recent widespread use of the material in visible light-emitting devices. A key topic has been the indirect determination of the composition by x-ray diffraction (XRD). We examine critically the several levels of approximation involved in this procedure. It is shown by extended x-ray absorption fine structure (EXAFS) measurements that the local structure of InGaN is independent of the composition, in the range of InN fraction, from about 15 to 40{\%}, that corresponds to blue to infrared light emission from this material. EXAFSdetermined ratios of the numbers of indium and gallium atoms in the first metal co-ordination shell, M1, show very good agreement with the composition measured by established techniques, both structural and chemical, on similar samples. On the other hand, the atomic separations deviate markedly from values calculated using Vegard's law. In particular, the average radial separations, In-N1 = 2.11(2) {\^i}.. and In-M1 = 3.28(3) {\^i}.., do not vary significantly with In/Ga ratio in the examined composition range. We conclude with some brief comments on the uncertain but challenging topic of InGaN nanostructure.",
keywords = "InGaN, light-emitting devices, x-ray diffraction, nanoscience",
author = "K.P. O'Donnell and J.F.W. Mosselmans and R.W. Martin and S. Pereira and M.E. White",
year = "2001",
month = "8",
day = "13",
doi = "10.1088/0953-8984/13/32/307",
language = "English",
volume = "13",
pages = "6977--6991",
journal = "Journal of Physics: Condensed Matter",
issn = "0953-8984",
number = "32",

}

Structural analysis of InGaN epilayers. / O'Donnell, K.P.; Mosselmans, J.F.W.; Martin, R.W.; Pereira, S.; White, M.E.

In: Journal of Physics: Condensed Matter, Vol. 13, No. 32, 13.08.2001, p. 6977-6991.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Structural analysis of InGaN epilayers

AU - O'Donnell, K.P.

AU - Mosselmans, J.F.W.

AU - Martin, R.W.

AU - Pereira, S.

AU - White, M.E.

PY - 2001/8/13

Y1 - 2001/8/13

N2 - The structural properties of InGaN have attracted interest on account of the recent widespread use of the material in visible light-emitting devices. A key topic has been the indirect determination of the composition by x-ray diffraction (XRD). We examine critically the several levels of approximation involved in this procedure. It is shown by extended x-ray absorption fine structure (EXAFS) measurements that the local structure of InGaN is independent of the composition, in the range of InN fraction, from about 15 to 40%, that corresponds to blue to infrared light emission from this material. EXAFSdetermined ratios of the numbers of indium and gallium atoms in the first metal co-ordination shell, M1, show very good agreement with the composition measured by established techniques, both structural and chemical, on similar samples. On the other hand, the atomic separations deviate markedly from values calculated using Vegard's law. In particular, the average radial separations, In-N1 = 2.11(2) î.. and In-M1 = 3.28(3) î.., do not vary significantly with In/Ga ratio in the examined composition range. We conclude with some brief comments on the uncertain but challenging topic of InGaN nanostructure.

AB - The structural properties of InGaN have attracted interest on account of the recent widespread use of the material in visible light-emitting devices. A key topic has been the indirect determination of the composition by x-ray diffraction (XRD). We examine critically the several levels of approximation involved in this procedure. It is shown by extended x-ray absorption fine structure (EXAFS) measurements that the local structure of InGaN is independent of the composition, in the range of InN fraction, from about 15 to 40%, that corresponds to blue to infrared light emission from this material. EXAFSdetermined ratios of the numbers of indium and gallium atoms in the first metal co-ordination shell, M1, show very good agreement with the composition measured by established techniques, both structural and chemical, on similar samples. On the other hand, the atomic separations deviate markedly from values calculated using Vegard's law. In particular, the average radial separations, In-N1 = 2.11(2) î.. and In-M1 = 3.28(3) î.., do not vary significantly with In/Ga ratio in the examined composition range. We conclude with some brief comments on the uncertain but challenging topic of InGaN nanostructure.

KW - InGaN

KW - light-emitting devices

KW - x-ray diffraction

KW - nanoscience

UR - http://dx.doi.org/10.1088/0953-8984/13/32/307

U2 - 10.1088/0953-8984/13/32/307

DO - 10.1088/0953-8984/13/32/307

M3 - Article

VL - 13

SP - 6977

EP - 6991

JO - Journal of Physics: Condensed Matter

T2 - Journal of Physics: Condensed Matter

JF - Journal of Physics: Condensed Matter

SN - 0953-8984

IS - 32

ER -