Electrical properties and deep traps spectra of a-plane GaN films grown on r-plane sapphire

A. Y. Polyakov, N. B. Smirnov, A. V. Govorkov, A. V. Markov, Q. Sun, Y. Zhang, C. D. Yerino, T. S. Ko, In-Hwan Lee, J. Han

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Electrical properties, deep traps spectra and luminescence spectra were studied for two undoped a-plane GaN (a-GaN) films grown on r-plane sapphire using metalorganic chemical vapor deposition and differing by structural perfection. For sample A, the a-GaN film was directly deposited on AlN buffer. A two-step growth scheme was implemented for sample B, including an initial islanding growth stage and a subsequent enhanced lateral growth. Preliminary detailed X-ray analysis showed that the stacking faults density was 8 × 105 cm-1 for sample A and 1.7 × 105 cm-1 for sample B. Electrical properties of a-GaN films were largely determined by deep traps with a level near Ec -0.6 eV, with other prominent traps having the activation energy of 0.25 eV. The Fermi level was pinned by the Ec -0.6 eV deep traps for sample A, but shifted to the vicinity of the shallower 0.25 eV traps for sample B, most likely due to the reduced density of the 0.6 eV traps. This decrease of deep traps density is accompanied by a very pronounced improvement in the overall luminescence intensity. A correlation of the observed improvement in deep traps spectra and luminescence efficiency with the improved crystalline quality of the films is discussed.

Original languageEnglish
Pages (from-to)220-224
Number of pages5
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Volume166
Issue number3
DOIs
Publication statusPublished - 2010 Feb 15
Externally publishedYes

Fingerprint

Aluminum Oxide
Sapphire
sapphire
Electric properties
electrical properties
traps
Luminescence
X ray analysis
Stacking faults
Metallorganic chemical vapor deposition
luminescence
Fermi level
Buffers
Activation energy
Crystalline materials
crystal defects
metalorganic chemical vapor deposition
buffers
activation energy

Keywords

  • Deep traps
  • Epitaxy
  • Extended defects
  • Group III-nitrides
  • Nonpolar

ASJC Scopus subject areas

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

Cite this

Electrical properties and deep traps spectra of a-plane GaN films grown on r-plane sapphire. / Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Markov, A. V.; Sun, Q.; Zhang, Y.; Yerino, C. D.; Ko, T. S.; Lee, In-Hwan; Han, J.

In: Materials Science and Engineering B: Solid-State Materials for Advanced Technology, Vol. 166, No. 3, 15.02.2010, p. 220-224.

Research output: Contribution to journalArticle

Polyakov, A. Y. ; Smirnov, N. B. ; Govorkov, A. V. ; Markov, A. V. ; Sun, Q. ; Zhang, Y. ; Yerino, C. D. ; Ko, T. S. ; Lee, In-Hwan ; Han, J. / Electrical properties and deep traps spectra of a-plane GaN films grown on r-plane sapphire. In: Materials Science and Engineering B: Solid-State Materials for Advanced Technology. 2010 ; Vol. 166, No. 3. pp. 220-224.
@article{137a1887960340329eb0d2b52db67be0,
title = "Electrical properties and deep traps spectra of a-plane GaN films grown on r-plane sapphire",
abstract = "Electrical properties, deep traps spectra and luminescence spectra were studied for two undoped a-plane GaN (a-GaN) films grown on r-plane sapphire using metalorganic chemical vapor deposition and differing by structural perfection. For sample A, the a-GaN film was directly deposited on AlN buffer. A two-step growth scheme was implemented for sample B, including an initial islanding growth stage and a subsequent enhanced lateral growth. Preliminary detailed X-ray analysis showed that the stacking faults density was 8 × 105 cm-1 for sample A and 1.7 × 105 cm-1 for sample B. Electrical properties of a-GaN films were largely determined by deep traps with a level near Ec -0.6 eV, with other prominent traps having the activation energy of 0.25 eV. The Fermi level was pinned by the Ec -0.6 eV deep traps for sample A, but shifted to the vicinity of the shallower 0.25 eV traps for sample B, most likely due to the reduced density of the 0.6 eV traps. This decrease of deep traps density is accompanied by a very pronounced improvement in the overall luminescence intensity. A correlation of the observed improvement in deep traps spectra and luminescence efficiency with the improved crystalline quality of the films is discussed.",
keywords = "Deep traps, Epitaxy, Extended defects, Group III-nitrides, Nonpolar",
author = "Polyakov, {A. Y.} and Smirnov, {N. B.} and Govorkov, {A. V.} and Markov, {A. V.} and Q. Sun and Y. Zhang and Yerino, {C. D.} and Ko, {T. S.} and In-Hwan Lee and J. Han",
year = "2010",
month = "2",
day = "15",
doi = "10.1016/j.mseb.2009.11.030",
language = "English",
volume = "166",
pages = "220--224",
journal = "Materials Science and Engineering B: Solid-State Materials for Advanced Technology",
issn = "0921-5107",
publisher = "Elsevier BV",
number = "3",

}

TY - JOUR

T1 - Electrical properties and deep traps spectra of a-plane GaN films grown on r-plane sapphire

AU - Polyakov, A. Y.

AU - Smirnov, N. B.

AU - Govorkov, A. V.

AU - Markov, A. V.

AU - Sun, Q.

AU - Zhang, Y.

AU - Yerino, C. D.

AU - Ko, T. S.

AU - Lee, In-Hwan

AU - Han, J.

PY - 2010/2/15

Y1 - 2010/2/15

N2 - Electrical properties, deep traps spectra and luminescence spectra were studied for two undoped a-plane GaN (a-GaN) films grown on r-plane sapphire using metalorganic chemical vapor deposition and differing by structural perfection. For sample A, the a-GaN film was directly deposited on AlN buffer. A two-step growth scheme was implemented for sample B, including an initial islanding growth stage and a subsequent enhanced lateral growth. Preliminary detailed X-ray analysis showed that the stacking faults density was 8 × 105 cm-1 for sample A and 1.7 × 105 cm-1 for sample B. Electrical properties of a-GaN films were largely determined by deep traps with a level near Ec -0.6 eV, with other prominent traps having the activation energy of 0.25 eV. The Fermi level was pinned by the Ec -0.6 eV deep traps for sample A, but shifted to the vicinity of the shallower 0.25 eV traps for sample B, most likely due to the reduced density of the 0.6 eV traps. This decrease of deep traps density is accompanied by a very pronounced improvement in the overall luminescence intensity. A correlation of the observed improvement in deep traps spectra and luminescence efficiency with the improved crystalline quality of the films is discussed.

AB - Electrical properties, deep traps spectra and luminescence spectra were studied for two undoped a-plane GaN (a-GaN) films grown on r-plane sapphire using metalorganic chemical vapor deposition and differing by structural perfection. For sample A, the a-GaN film was directly deposited on AlN buffer. A two-step growth scheme was implemented for sample B, including an initial islanding growth stage and a subsequent enhanced lateral growth. Preliminary detailed X-ray analysis showed that the stacking faults density was 8 × 105 cm-1 for sample A and 1.7 × 105 cm-1 for sample B. Electrical properties of a-GaN films were largely determined by deep traps with a level near Ec -0.6 eV, with other prominent traps having the activation energy of 0.25 eV. The Fermi level was pinned by the Ec -0.6 eV deep traps for sample A, but shifted to the vicinity of the shallower 0.25 eV traps for sample B, most likely due to the reduced density of the 0.6 eV traps. This decrease of deep traps density is accompanied by a very pronounced improvement in the overall luminescence intensity. A correlation of the observed improvement in deep traps spectra and luminescence efficiency with the improved crystalline quality of the films is discussed.

KW - Deep traps

KW - Epitaxy

KW - Extended defects

KW - Group III-nitrides

KW - Nonpolar

UR - http://www.scopus.com/inward/record.url?scp=74349122306&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=74349122306&partnerID=8YFLogxK

U2 - 10.1016/j.mseb.2009.11.030

DO - 10.1016/j.mseb.2009.11.030

M3 - Article

AN - SCOPUS:74349122306

VL - 166

SP - 220

EP - 224

JO - Materials Science and Engineering B: Solid-State Materials for Advanced Technology

JF - Materials Science and Engineering B: Solid-State Materials for Advanced Technology

SN - 0921-5107

IS - 3

ER -