Cathodoluminescence studies of chevron features in semi-polar (11-22) InGaN/GaN multiple quantum well structures

C. Brasser, J. Bruckbauer, Y.P. Gong, L. Jiu, J. Bai, M. Warzecha, P. R. Edwards, T. Wang, R. W. Martin

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Abstract

Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural and electrical properties of these features occurring in two very different semi-polar structures, a blue-emitting multiple quantum well (MQW) structure and an amber-emitting light-emitting diode (LED). Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the QWs in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample, and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current (EBIC). Overall these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices.
LanguageEnglish
Article number174502
Number of pages7
JournalJournal of Applied Physics
Volume123
DOIs
StatePublished - 1 May 2018

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cathodoluminescence
quantum wells
nitrides
light emission
light emitting diodes
electrical properties
atomic force microscopy
electron beams
luminescence
optical properties
causes
shift
energy

Keywords

  • semi-polar structures
  • cathodoluminescence

Cite this

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title = "Cathodoluminescence studies of chevron features in semi-polar (11-22) InGaN/GaN multiple quantum well structures",
abstract = "Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural and electrical properties of these features occurring in two very different semi-polar structures, a blue-emitting multiple quantum well (MQW) structure and an amber-emitting light-emitting diode (LED). Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the QWs in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample, and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current (EBIC). Overall these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices.",
keywords = "semi-polar structures, cathodoluminescence",
author = "C. Brasser and J. Bruckbauer and Y.P. Gong and L. Jiu and J. Bai and M. Warzecha and Edwards, {P. R.} and T. Wang and Martin, {R. W.}",
year = "2018",
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T1 - Cathodoluminescence studies of chevron features in semi-polar (11-22) InGaN/GaN multiple quantum well structures

AU - Brasser,C.

AU - Bruckbauer,J.

AU - Gong,Y.P.

AU - Jiu,L.

AU - Bai,J.

AU - Warzecha,M.

AU - Edwards,P. R.

AU - Wang,T.

AU - Martin,R. W.

PY - 2018/5/1

Y1 - 2018/5/1

N2 - Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural and electrical properties of these features occurring in two very different semi-polar structures, a blue-emitting multiple quantum well (MQW) structure and an amber-emitting light-emitting diode (LED). Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the QWs in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample, and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current (EBIC). Overall these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices.

AB - Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural and electrical properties of these features occurring in two very different semi-polar structures, a blue-emitting multiple quantum well (MQW) structure and an amber-emitting light-emitting diode (LED). Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the QWs in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample, and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current (EBIC). Overall these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices.

KW - semi-polar structures

KW - cathodoluminescence

UR - https://aip.scitation.org/journal/jap/

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DO - 10.1063/1.5021883

M3 - Article

VL - 123

JO - Journal of Applied Physics

T2 - Journal of Applied Physics

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