Optical studies on the red luminescence of InGaN epilayers

M.R. Correia, S.M.D.S. Pereira, E.M. Ferreira Pereira Lopes, R.A.S. Ferreira, J. Frandon, E. Alves, I.M. Watson, C. Liu, A. Morel, B. Gil

Research output: Contribution to journalArticle

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Abstract

Photoluminescence, photoluminescence excitation and time-resolved photoluminescence studies were performed in a partially relaxed InGaN epilayer, and exhibiting a 3D growth mode at the surface. Two emission bands, a red (centred at ∼1.88 eV) and a blue (centred at ∼2.58 eV) were observed. In order to investigate their origin and their relation with the strain relaxation along the growth direction, the sample was etched. After etching, only an asymmetrical broad emission band centred at ∼2.15 eV was observed. The decrease of decay time and the increase of the band edge absorption energy with increasing monitored photon energy, along the red emission, are assigned to the effect of localization of excitons at potential minima, originated in compositional and strain inhomogeneities of the sample. Therefore, the blue shift observed on this band with an increase in temperature, is caused by the population of higher energy states. The large difference between the luminescence intensities, decay times and the thermal quenching of the red and blue (centred at ∼2.58 eV) band is also accounted for by the localization model. It is demonstrated that the luminescence observed after etching is a superposition of two bands, one originated from the InGaN film, and the other from the GaN underlayer. The large difference between absorption and emission energies, compared with those measured in the as-grown sample, within the same spectral region, indicates that this emission has a different origin. It is suggested that deep levels might be responsible for the luminescence observed after etching.
LanguageEnglish
Pages625-632
Number of pages8
JournalSuperlattices and Microstructures
Volume36
Issue number4-6
DOIs
Publication statusPublished - 2004

Fingerprint

Epilayers
Luminescence
Etching
Photoluminescence
luminescence
Strain relaxation
etching
photoluminescence
Excitons
Electron energy levels
Quenching
Photons
energy absorption
decay
blue shift
energy
inhomogeneity
quenching
excitons
Temperature

Keywords

  • luminescence
  • InGaN epilayers
  • microstructures

Cite this

Correia, M. R., Pereira, S. M. D. S., Ferreira Pereira Lopes, E. M., Ferreira, R. A. S., Frandon, J., Alves, E., ... Gil, B. (2004). Optical studies on the red luminescence of InGaN epilayers. Superlattices and Microstructures, 36(4-6), 625-632. https://doi.org/10.1016/j.spmi.2004.09.020
Correia, M.R. ; Pereira, S.M.D.S. ; Ferreira Pereira Lopes, E.M. ; Ferreira, R.A.S. ; Frandon, J. ; Alves, E. ; Watson, I.M. ; Liu, C. ; Morel, A. ; Gil, B. / Optical studies on the red luminescence of InGaN epilayers. In: Superlattices and Microstructures. 2004 ; Vol. 36, No. 4-6. pp. 625-632.
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keywords = "luminescence , InGaN epilayers , microstructures",
author = "M.R. Correia and S.M.D.S. Pereira and {Ferreira Pereira Lopes}, E.M. and R.A.S. Ferreira and J. Frandon and E. Alves and I.M. Watson and C. Liu and A. Morel and B. Gil",
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Correia, MR, Pereira, SMDS, Ferreira Pereira Lopes, EM, Ferreira, RAS, Frandon, J, Alves, E, Watson, IM, Liu, C, Morel, A & Gil, B 2004, 'Optical studies on the red luminescence of InGaN epilayers' Superlattices and Microstructures, vol. 36, no. 4-6, pp. 625-632. https://doi.org/10.1016/j.spmi.2004.09.020

Optical studies on the red luminescence of InGaN epilayers. / Correia, M.R.; Pereira, S.M.D.S.; Ferreira Pereira Lopes, E.M.; Ferreira, R.A.S.; Frandon, J.; Alves, E.; Watson, I.M.; Liu, C.; Morel, A.; Gil, B.

In: Superlattices and Microstructures, Vol. 36, No. 4-6, 2004, p. 625-632.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Optical studies on the red luminescence of InGaN epilayers

AU - Correia, M.R.

AU - Pereira, S.M.D.S.

AU - Ferreira Pereira Lopes, E.M.

AU - Ferreira, R.A.S.

AU - Frandon, J.

AU - Alves, E.

AU - Watson, I.M.

AU - Liu, C.

AU - Morel, A.

AU - Gil, B.

PY - 2004

Y1 - 2004

N2 - Photoluminescence, photoluminescence excitation and time-resolved photoluminescence studies were performed in a partially relaxed InGaN epilayer, and exhibiting a 3D growth mode at the surface. Two emission bands, a red (centred at ∼1.88 eV) and a blue (centred at ∼2.58 eV) were observed. In order to investigate their origin and their relation with the strain relaxation along the growth direction, the sample was etched. After etching, only an asymmetrical broad emission band centred at ∼2.15 eV was observed. The decrease of decay time and the increase of the band edge absorption energy with increasing monitored photon energy, along the red emission, are assigned to the effect of localization of excitons at potential minima, originated in compositional and strain inhomogeneities of the sample. Therefore, the blue shift observed on this band with an increase in temperature, is caused by the population of higher energy states. The large difference between the luminescence intensities, decay times and the thermal quenching of the red and blue (centred at ∼2.58 eV) band is also accounted for by the localization model. It is demonstrated that the luminescence observed after etching is a superposition of two bands, one originated from the InGaN film, and the other from the GaN underlayer. The large difference between absorption and emission energies, compared with those measured in the as-grown sample, within the same spectral region, indicates that this emission has a different origin. It is suggested that deep levels might be responsible for the luminescence observed after etching.

AB - Photoluminescence, photoluminescence excitation and time-resolved photoluminescence studies were performed in a partially relaxed InGaN epilayer, and exhibiting a 3D growth mode at the surface. Two emission bands, a red (centred at ∼1.88 eV) and a blue (centred at ∼2.58 eV) were observed. In order to investigate their origin and their relation with the strain relaxation along the growth direction, the sample was etched. After etching, only an asymmetrical broad emission band centred at ∼2.15 eV was observed. The decrease of decay time and the increase of the band edge absorption energy with increasing monitored photon energy, along the red emission, are assigned to the effect of localization of excitons at potential minima, originated in compositional and strain inhomogeneities of the sample. Therefore, the blue shift observed on this band with an increase in temperature, is caused by the population of higher energy states. The large difference between the luminescence intensities, decay times and the thermal quenching of the red and blue (centred at ∼2.58 eV) band is also accounted for by the localization model. It is demonstrated that the luminescence observed after etching is a superposition of two bands, one originated from the InGaN film, and the other from the GaN underlayer. The large difference between absorption and emission energies, compared with those measured in the as-grown sample, within the same spectral region, indicates that this emission has a different origin. It is suggested that deep levels might be responsible for the luminescence observed after etching.

KW - luminescence

KW - InGaN epilayers

KW - microstructures

U2 - 10.1016/j.spmi.2004.09.020

DO - 10.1016/j.spmi.2004.09.020

M3 - Article

VL - 36

SP - 625

EP - 632

JO - Superlattices and Microstructures

T2 - Superlattices and Microstructures

JF - Superlattices and Microstructures

SN - 0749-6036

IS - 4-6

ER -

Correia MR, Pereira SMDS, Ferreira Pereira Lopes EM, Ferreira RAS, Frandon J, Alves E et al. Optical studies on the red luminescence of InGaN epilayers. Superlattices and Microstructures. 2004;36(4-6):625-632. https://doi.org/10.1016/j.spmi.2004.09.020