Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy

S. K. Han, S. K. Hong, J. W. Lee, J. Y. Lee, J. H. Song, Y. S. Nam, S. K. Chang, T. Minegishi, T. Yao

Research output: Contribution to journalArticle

77 Citations (Scopus)

Abstract

Non-polar, A-plane (1 1 over(2, -) 0) ZnO films are epitaxially grown on R-plane (1 over(1, -) 0 2) Al2O3 substrates by plasma-assisted molecular-beam epitaxy and structural and optical properties are investigated. Epitaxial relationships between ZnO films and Al2O3 substrates are determined to be ZnO(1 1 over(2, -) 0) / / Al2 O3 (1 over(1, -) 2 0), ZnO[over(1, -) 1 0 0] / / Al2 O3 [1 1 over(2, -) 0]. The misfit is relaxed by the regularly spaced misfit dislocations. Structural properties are anisotropic and surfaces of films show stripes running along the ZnO [0 0 0 1] direction. Full width at half maximums of X-ray rocking curves for the on-axis (1 1 over(2, -) 0) with φ=0° and 90°, and the off-axis (1 0 over(1, -) 1) reflections are 0.41°, 0.36°, and 0.39°, respectively, for the 300 nm-thick ZnO film. Near-band edge emissions are dominant in low-temperature (12 K) photoluminescence while emissions from deep levels are negligible indicating a high optical quality of the layers. The near-band edge emissions are strongly polarized perpendicular to the [0 0 0 1] axis. Transitions of neutral-donor bound excitons (D0X) and allowed free excitons are observed in photoluminescence and photoreflectance spectra, which are significantly blue-shifted compared to the transitions in C-plane ZnO.

Original languageEnglish
Pages (from-to)121-127
Number of pages7
JournalJournal of Crystal Growth
Volume309
Issue number2
DOIs
Publication statusPublished - 2007 Dec 1

Fingerprint

Aluminum Oxide
Molecular beam epitaxy
Sapphire
Structural properties
sapphire
molecular beam epitaxy
Optical properties
Plasmas
optical properties
Excitons
Photoluminescence
Substrates
excitons
photoluminescence
Electron transitions
Full width at half maximum
Dislocations (crystals)
Thick films
thick films
X rays

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Han, S. K. ; Hong, S. K. ; Lee, J. W. ; Lee, J. Y. ; Song, J. H. ; Nam, Y. S. ; Chang, S. K. ; Minegishi, T. ; Yao, T. / Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy. In: Journal of Crystal Growth. 2007 ; Vol. 309, No. 2. pp. 121-127.
@article{b0c7d744ce4b4ea7b5784d4daa230a71,
title = "Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy",
abstract = "Non-polar, A-plane (1 1 over(2, -) 0) ZnO films are epitaxially grown on R-plane (1 over(1, -) 0 2) Al2O3 substrates by plasma-assisted molecular-beam epitaxy and structural and optical properties are investigated. Epitaxial relationships between ZnO films and Al2O3 substrates are determined to be ZnO(1 1 over(2, -) 0) / / Al2 O3 (1 over(1, -) 2 0), ZnO[over(1, -) 1 0 0] / / Al2 O3 [1 1 over(2, -) 0]. The misfit is relaxed by the regularly spaced misfit dislocations. Structural properties are anisotropic and surfaces of films show stripes running along the ZnO [0 0 0 1] direction. Full width at half maximums of X-ray rocking curves for the on-axis (1 1 over(2, -) 0) with φ=0° and 90°, and the off-axis (1 0 over(1, -) 1) reflections are 0.41°, 0.36°, and 0.39°, respectively, for the 300 nm-thick ZnO film. Near-band edge emissions are dominant in low-temperature (12 K) photoluminescence while emissions from deep levels are negligible indicating a high optical quality of the layers. The near-band edge emissions are strongly polarized perpendicular to the [0 0 0 1] axis. Transitions of neutral-donor bound excitons (D0X) and allowed free excitons are observed in photoluminescence and photoreflectance spectra, which are significantly blue-shifted compared to the transitions in C-plane ZnO.",
author = "Han, {S. K.} and Hong, {S. K.} and Lee, {J. W.} and Lee, {J. Y.} and Song, {J. H.} and Nam, {Y. S.} and Chang, {S. K.} and T. Minegishi and T. Yao",
year = "2007",
month = "12",
day = "1",
doi = "10.1016/j.jcrysgro.2007.09.025",
language = "English",
volume = "309",
pages = "121--127",
journal = "Journal of Crystal Growth",
issn = "0022-0248",
publisher = "Elsevier",
number = "2",

}

Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy. / Han, S. K.; Hong, S. K.; Lee, J. W.; Lee, J. Y.; Song, J. H.; Nam, Y. S.; Chang, S. K.; Minegishi, T.; Yao, T.

In: Journal of Crystal Growth, Vol. 309, No. 2, 01.12.2007, p. 121-127.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Structural and optical properties of non-polar A-plane ZnO films grown on R-plane sapphire substrates by plasma-assisted molecular-beam epitaxy

AU - Han, S. K.

AU - Hong, S. K.

AU - Lee, J. W.

AU - Lee, J. Y.

AU - Song, J. H.

AU - Nam, Y. S.

AU - Chang, S. K.

AU - Minegishi, T.

AU - Yao, T.

PY - 2007/12/1

Y1 - 2007/12/1

N2 - Non-polar, A-plane (1 1 over(2, -) 0) ZnO films are epitaxially grown on R-plane (1 over(1, -) 0 2) Al2O3 substrates by plasma-assisted molecular-beam epitaxy and structural and optical properties are investigated. Epitaxial relationships between ZnO films and Al2O3 substrates are determined to be ZnO(1 1 over(2, -) 0) / / Al2 O3 (1 over(1, -) 2 0), ZnO[over(1, -) 1 0 0] / / Al2 O3 [1 1 over(2, -) 0]. The misfit is relaxed by the regularly spaced misfit dislocations. Structural properties are anisotropic and surfaces of films show stripes running along the ZnO [0 0 0 1] direction. Full width at half maximums of X-ray rocking curves for the on-axis (1 1 over(2, -) 0) with φ=0° and 90°, and the off-axis (1 0 over(1, -) 1) reflections are 0.41°, 0.36°, and 0.39°, respectively, for the 300 nm-thick ZnO film. Near-band edge emissions are dominant in low-temperature (12 K) photoluminescence while emissions from deep levels are negligible indicating a high optical quality of the layers. The near-band edge emissions are strongly polarized perpendicular to the [0 0 0 1] axis. Transitions of neutral-donor bound excitons (D0X) and allowed free excitons are observed in photoluminescence and photoreflectance spectra, which are significantly blue-shifted compared to the transitions in C-plane ZnO.

AB - Non-polar, A-plane (1 1 over(2, -) 0) ZnO films are epitaxially grown on R-plane (1 over(1, -) 0 2) Al2O3 substrates by plasma-assisted molecular-beam epitaxy and structural and optical properties are investigated. Epitaxial relationships between ZnO films and Al2O3 substrates are determined to be ZnO(1 1 over(2, -) 0) / / Al2 O3 (1 over(1, -) 2 0), ZnO[over(1, -) 1 0 0] / / Al2 O3 [1 1 over(2, -) 0]. The misfit is relaxed by the regularly spaced misfit dislocations. Structural properties are anisotropic and surfaces of films show stripes running along the ZnO [0 0 0 1] direction. Full width at half maximums of X-ray rocking curves for the on-axis (1 1 over(2, -) 0) with φ=0° and 90°, and the off-axis (1 0 over(1, -) 1) reflections are 0.41°, 0.36°, and 0.39°, respectively, for the 300 nm-thick ZnO film. Near-band edge emissions are dominant in low-temperature (12 K) photoluminescence while emissions from deep levels are negligible indicating a high optical quality of the layers. The near-band edge emissions are strongly polarized perpendicular to the [0 0 0 1] axis. Transitions of neutral-donor bound excitons (D0X) and allowed free excitons are observed in photoluminescence and photoreflectance spectra, which are significantly blue-shifted compared to the transitions in C-plane ZnO.

UR - http://www.scopus.com/inward/record.url?scp=36049004670&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=36049004670&partnerID=8YFLogxK

U2 - 10.1016/j.jcrysgro.2007.09.025

DO - 10.1016/j.jcrysgro.2007.09.025

M3 - Article

AN - SCOPUS:36049004670

VL - 309

SP - 121

EP - 127

JO - Journal of Crystal Growth

JF - Journal of Crystal Growth

SN - 0022-0248

IS - 2

ER -