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

Autor: Matthew J. Davies, Darren M. Graham, Ben F. Spencer, Samantha J. O. Hardman, Simon Hammersley, Colin J. Humphreys, Menno J. Kappers, Phil Dawson, Rachel A. Oliver, Aniela Dunn
Rok vydání: 2016
Předmět:
Zdroj: 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, pp. 252-255 . https://doi.org/10.1002/pssc.201510193
ISSN: 1610-1642
1862-6351
Popis: 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. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Databáze: OpenAIRE
Externí odkaz: