Investigating efficiency droop in InGaN/GaN quantum well structures using ultrafast time-resolved terahertz and photoluminescence spectroscopy

Aniela Dunn; Ben F. Spencer; Samantha J. O. Hardman; Darren M. Graham; Simon Hammersley; Matthew Davies; Philip Dawson; Menno J. Kappers; Rachel A. Oliver; Colin J. Humphreys

doi:10.1002/pssc.201510193

Investigating efficiency droop in InGaN/GaN quantum well structures using ultrafast time-resolved terahertz and photoluminescence spectroscopy

Aniela Dunn, Ben F. Spencer, Samantha J. O. Hardman, Darren M. Graham, Simon Hammersley, Matthew Davies, Philip Dawson, Menno J. Kappers, Rachel A. Oliver, Colin J. Humphreys

Research output: Contribution to journal › Article › peer-review

Abstract

The mechanisms governing efficiency droop in an In0.18Ga0.82N/GaN multiple quantum well structure were investigated using a combination of ultrafast time-resolved terahertz and photoluminescence spectroscopy. From excitation fluence dependent studies, a reduction in the room temperature photoluminescence efficiency to 3% of its maximum value was observed for an excitation fluence of 0.96 mJcm-2. A correlation was found between the onset of efficiency droop and the emergence of a peak on the high-energy side of the quantum well emission with a 1/e decay time of 19.6 ps. These characteristics were attributed to the saturation of localised states and the population of higher energy delocalised states. Time-resolved studies revealed different scaling behaviours between the terahertz and photoluminescence decay dynamics, suggesting that the saturation of localised hole states may be playing a part in the onset of efficiency droop

Original language	English
Pages (from-to)	252-255
Journal	Physica Status Solidi. C: Current Topics in Solid State Physics
Early online date	3 Feb 2016
DOIs	https://doi.org/10.1002/pssc.201510193
Publication status	Published - May 2016

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Dunn, A., Spencer, B. F., Hardman, S. J. O., Graham, D. M., Hammersley, S., Davies, M., Dawson, P., Kappers, M. J., Oliver, R. A., & Humphreys, C. J. (2016). Investigating efficiency droop in InGaN/GaN quantum well structures using ultrafast time-resolved terahertz and photoluminescence spectroscopy. Physica Status Solidi. C: Current Topics in Solid State Physics, 252-255. https://doi.org/10.1002/pssc.201510193

@article{dd7409f56b0a41279090f78ce4f533f3,

title = "Investigating efficiency droop in InGaN/GaN quantum well structures using ultrafast time-resolved terahertz and photoluminescence spectroscopy",

abstract = "The mechanisms governing efficiency droop in an In0.18Ga0.82N/GaN multiple quantum well structure were investigated using a combination of ultrafast time-resolved terahertz and photoluminescence spectroscopy. From excitation fluence dependent studies, a reduction in the room temperature photoluminescence efficiency to 3% of its maximum value was observed for an excitation fluence of 0.96 mJcm-2. A correlation was found between the onset of efficiency droop and the emergence of a peak on the high-energy side of the quantum well emission with a 1/e decay time of 19.6 ps. These characteristics were attributed to the saturation of localised states and the population of higher energy delocalised states. Time-resolved studies revealed different scaling behaviours between the terahertz and photoluminescence decay dynamics, suggesting that the saturation of localised hole states may be playing a part in the onset of efficiency droop",

author = "Aniela Dunn and Spencer, {Ben F.} and Hardman, {Samantha J. O.} and Graham, {Darren M.} and Simon Hammersley and Matthew Davies and Philip Dawson and Kappers, {Menno J.} and Oliver, {Rachel A.} and Humphreys, {Colin J.}",

year = "2016",

month = may,

doi = "10.1002/pssc.201510193",

language = "English",

pages = "252--255",

journal = "Physica Status Solidi. C: Current Topics in Solid State Physics",

issn = "1862-6351",

publisher = "John Wiley & Sons Ltd",

}

Dunn, A, Spencer, BF, Hardman, SJO, Graham, DM, Hammersley, S, Davies, M, Dawson, P, Kappers, MJ, Oliver, RA & Humphreys, CJ 2016, 'Investigating efficiency droop in InGaN/GaN quantum well structures using ultrafast time-resolved terahertz and photoluminescence spectroscopy', Physica Status Solidi. C: Current Topics in Solid State Physics, pp. 252-255. https://doi.org/10.1002/pssc.201510193

TY - JOUR

T1 - Investigating efficiency droop in InGaN/GaN quantum well structures using ultrafast time-resolved terahertz and photoluminescence spectroscopy

AU - Dunn, Aniela

AU - Spencer, Ben F.

AU - Hardman, Samantha J. O.

AU - Graham, Darren M.

AU - Hammersley, Simon

AU - Davies, Matthew

AU - Dawson, Philip

AU - Kappers, Menno J.

AU - Oliver, Rachel A.

AU - Humphreys, Colin J.

PY - 2016/5

Y1 - 2016/5

N2 - The mechanisms governing efficiency droop in an In0.18Ga0.82N/GaN multiple quantum well structure were investigated using a combination of ultrafast time-resolved terahertz and photoluminescence spectroscopy. From excitation fluence dependent studies, a reduction in the room temperature photoluminescence efficiency to 3% of its maximum value was observed for an excitation fluence of 0.96 mJcm-2. A correlation was found between the onset of efficiency droop and the emergence of a peak on the high-energy side of the quantum well emission with a 1/e decay time of 19.6 ps. These characteristics were attributed to the saturation of localised states and the population of higher energy delocalised states. Time-resolved studies revealed different scaling behaviours between the terahertz and photoluminescence decay dynamics, suggesting that the saturation of localised hole states may be playing a part in the onset of efficiency droop

AB - The mechanisms governing efficiency droop in an In0.18Ga0.82N/GaN multiple quantum well structure were investigated using a combination of ultrafast time-resolved terahertz and photoluminescence spectroscopy. From excitation fluence dependent studies, a reduction in the room temperature photoluminescence efficiency to 3% of its maximum value was observed for an excitation fluence of 0.96 mJcm-2. A correlation was found between the onset of efficiency droop and the emergence of a peak on the high-energy side of the quantum well emission with a 1/e decay time of 19.6 ps. These characteristics were attributed to the saturation of localised states and the population of higher energy delocalised states. Time-resolved studies revealed different scaling behaviours between the terahertz and photoluminescence decay dynamics, suggesting that the saturation of localised hole states may be playing a part in the onset of efficiency droop

U2 - 10.1002/pssc.201510193

DO - 10.1002/pssc.201510193

M3 - Article

SN - 1862-6351

SP - 252

EP - 255

JO - Physica Status Solidi. C: Current Topics in Solid State Physics

JF - Physica Status Solidi. C: Current Topics in Solid State Physics

ER -

Investigating efficiency droop in InGaN/GaN quantum well structures using ultrafast time-resolved terahertz and photoluminescence spectroscopy

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