Spatial variation of luminescence of InGaN alloys measured by highly-spatially-resolved scanning cathodoluminescence

F. Bertram, S. Srinivasan, R. Liu, L. Geng, Fernando Ponce, T. Riemann, J. Christen, S. Tanaka, H. Omiya, Y. Nakagawa

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Cathodoluminescence (CL) measurements were performed on thick InGaN samples over a wide range of indium concentrations ([ln] = 0.03 - 0.20). The layers were grown on c-plane sapphire using an AlGaN buffer layer, followed by 4 μm GaN, and 100 nm InGaN films. These thick InGaN layers were exceptionally specular, especially at low indium concentrations. Some degree of microscopic roughness was observed for x > 0.15. With the objective of correlating the microstructure to the spatial dependence of the luminescence, average CL spectra over large areas were compared with high-spatial-resolution CL measurements. The variation of the indium-related peaks over large areas was observed under low magnification scanned CL. The full width at half-maximum in the spot mode is typically smaller than wide-area scans by a factor of 2 to 3. The size of the areas with constant emission wavelength changes significantly with indium content. It has also been observed that the distribution of the local CL peak wavelength changes from single-mode Gaussian to a multimodal distribution for x > 0.1. A shoulder of the main peak at the low energy side appears at higher indium content. Spot-mode spectra show that this low energy shoulder consists of single lines at specific wavelengths. In highly resolved monochromatic images we correlate the low energy side shoulder to two structural defects: pinholes and grooves. Particularly, bright luminescence occurs at the center of the grooves.

Original languageEnglish (US)
Pages (from-to)19-23
Number of pages5
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Volume93
Issue number1-3
DOIs
StatePublished - May 30 2002

Fingerprint

Indium
Cathodoluminescence
cathodoluminescence
indium
Luminescence
luminescence
Scanning
shoulders
scanning
grooves
Wavelength
wavelengths
Aluminum Oxide
pinholes
Buffer layers
Full width at half maximum
magnification
Sapphire
energy
sapphire

Keywords

  • Cathodoluminescence
  • InGaN
  • Inversion domains
  • Phase separation
  • Pinholes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Spatial variation of luminescence of InGaN alloys measured by highly-spatially-resolved scanning cathodoluminescence. / Bertram, F.; Srinivasan, S.; Liu, R.; Geng, L.; Ponce, Fernando; Riemann, T.; Christen, J.; Tanaka, S.; Omiya, H.; Nakagawa, Y.

In: Materials Science and Engineering B: Solid-State Materials for Advanced Technology, Vol. 93, No. 1-3, 30.05.2002, p. 19-23.

Research output: Contribution to journalArticle

Bertram, F. ; Srinivasan, S. ; Liu, R. ; Geng, L. ; Ponce, Fernando ; Riemann, T. ; Christen, J. ; Tanaka, S. ; Omiya, H. ; Nakagawa, Y. / Spatial variation of luminescence of InGaN alloys measured by highly-spatially-resolved scanning cathodoluminescence. In: Materials Science and Engineering B: Solid-State Materials for Advanced Technology. 2002 ; Vol. 93, No. 1-3. pp. 19-23.
@article{9d487fd6bb85435898986851cebd455d,
title = "Spatial variation of luminescence of InGaN alloys measured by highly-spatially-resolved scanning cathodoluminescence",
abstract = "Cathodoluminescence (CL) measurements were performed on thick InGaN samples over a wide range of indium concentrations ([ln] = 0.03 - 0.20). The layers were grown on c-plane sapphire using an AlGaN buffer layer, followed by 4 μm GaN, and 100 nm InGaN films. These thick InGaN layers were exceptionally specular, especially at low indium concentrations. Some degree of microscopic roughness was observed for x > 0.15. With the objective of correlating the microstructure to the spatial dependence of the luminescence, average CL spectra over large areas were compared with high-spatial-resolution CL measurements. The variation of the indium-related peaks over large areas was observed under low magnification scanned CL. The full width at half-maximum in the spot mode is typically smaller than wide-area scans by a factor of 2 to 3. The size of the areas with constant emission wavelength changes significantly with indium content. It has also been observed that the distribution of the local CL peak wavelength changes from single-mode Gaussian to a multimodal distribution for x > 0.1. A shoulder of the main peak at the low energy side appears at higher indium content. Spot-mode spectra show that this low energy shoulder consists of single lines at specific wavelengths. In highly resolved monochromatic images we correlate the low energy side shoulder to two structural defects: pinholes and grooves. Particularly, bright luminescence occurs at the center of the grooves.",
keywords = "Cathodoluminescence, InGaN, Inversion domains, Phase separation, Pinholes",
author = "F. Bertram and S. Srinivasan and R. Liu and L. Geng and Fernando Ponce and T. Riemann and J. Christen and S. Tanaka and H. Omiya and Y. Nakagawa",
year = "2002",
month = "5",
day = "30",
doi = "10.1016/S0921-5107(02)00009-0",
language = "English (US)",
volume = "93",
pages = "19--23",
journal = "Materials Science and Engineering B: Solid-State Materials for Advanced Technology",
issn = "0921-5107",
publisher = "Elsevier BV",
number = "1-3",

}

TY - JOUR

T1 - Spatial variation of luminescence of InGaN alloys measured by highly-spatially-resolved scanning cathodoluminescence

AU - Bertram, F.

AU - Srinivasan, S.

AU - Liu, R.

AU - Geng, L.

AU - Ponce, Fernando

AU - Riemann, T.

AU - Christen, J.

AU - Tanaka, S.

AU - Omiya, H.

AU - Nakagawa, Y.

PY - 2002/5/30

Y1 - 2002/5/30

N2 - Cathodoluminescence (CL) measurements were performed on thick InGaN samples over a wide range of indium concentrations ([ln] = 0.03 - 0.20). The layers were grown on c-plane sapphire using an AlGaN buffer layer, followed by 4 μm GaN, and 100 nm InGaN films. These thick InGaN layers were exceptionally specular, especially at low indium concentrations. Some degree of microscopic roughness was observed for x > 0.15. With the objective of correlating the microstructure to the spatial dependence of the luminescence, average CL spectra over large areas were compared with high-spatial-resolution CL measurements. The variation of the indium-related peaks over large areas was observed under low magnification scanned CL. The full width at half-maximum in the spot mode is typically smaller than wide-area scans by a factor of 2 to 3. The size of the areas with constant emission wavelength changes significantly with indium content. It has also been observed that the distribution of the local CL peak wavelength changes from single-mode Gaussian to a multimodal distribution for x > 0.1. A shoulder of the main peak at the low energy side appears at higher indium content. Spot-mode spectra show that this low energy shoulder consists of single lines at specific wavelengths. In highly resolved monochromatic images we correlate the low energy side shoulder to two structural defects: pinholes and grooves. Particularly, bright luminescence occurs at the center of the grooves.

AB - Cathodoluminescence (CL) measurements were performed on thick InGaN samples over a wide range of indium concentrations ([ln] = 0.03 - 0.20). The layers were grown on c-plane sapphire using an AlGaN buffer layer, followed by 4 μm GaN, and 100 nm InGaN films. These thick InGaN layers were exceptionally specular, especially at low indium concentrations. Some degree of microscopic roughness was observed for x > 0.15. With the objective of correlating the microstructure to the spatial dependence of the luminescence, average CL spectra over large areas were compared with high-spatial-resolution CL measurements. The variation of the indium-related peaks over large areas was observed under low magnification scanned CL. The full width at half-maximum in the spot mode is typically smaller than wide-area scans by a factor of 2 to 3. The size of the areas with constant emission wavelength changes significantly with indium content. It has also been observed that the distribution of the local CL peak wavelength changes from single-mode Gaussian to a multimodal distribution for x > 0.1. A shoulder of the main peak at the low energy side appears at higher indium content. Spot-mode spectra show that this low energy shoulder consists of single lines at specific wavelengths. In highly resolved monochromatic images we correlate the low energy side shoulder to two structural defects: pinholes and grooves. Particularly, bright luminescence occurs at the center of the grooves.

KW - Cathodoluminescence

KW - InGaN

KW - Inversion domains

KW - Phase separation

KW - Pinholes

UR - http://www.scopus.com/inward/record.url?scp=0037198540&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037198540&partnerID=8YFLogxK

U2 - 10.1016/S0921-5107(02)00009-0

DO - 10.1016/S0921-5107(02)00009-0

M3 - Article

AN - SCOPUS:0037198540

VL - 93

SP - 19

EP - 23

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 - 1-3

ER -