Effect of carbon nanotube pattern on the laser lift off and quantum efficiencies of near UV vertical LEDs

Effect of carbon nanotube pattern on the laser lift off and quantum efficiencies of near UV vertical LEDs

Nowadays, ultraviolet light emitting diodes (UVLEDs) have aroused great interest in past few years for their promising application in adhesive curing, security identification and solid-state lighting etc. In gallium nitride (GaN) based LEDs, the patterned substrates and vertical devices' struct...

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Bibliographic Details
Published in:Journal of luminescence Vol. 234; p. 117938
Main Authors: Tian, M.F., Huang, L.H., Mei, Y., Xu, R.B., Zheng, Z.M., Su, X.L., Long, H., Ying, L.Y., Zhang, B.P., Wang, K., Yu, T.J.
Format: Journal Article
Language:English
Published: Elsevier B.V 01-06-2021
Subjects:
Carbon nanotube
GaN
Quantum efficiency
Ultraviolet light
Vertical LED
Carbon nanotube
Ultraviolet light
Quantum efficiency
Vertical LED
GaN
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Summary:Nowadays, ultraviolet light emitting diodes (UVLEDs) have aroused great interest in past few years for their promising application in adhesive curing, security identification and solid-state lighting etc. In gallium nitride (GaN) based LEDs, the patterned substrates and vertical devices' structure both played pivotal roles in elevating devices' performance. In this work, vertical near-UV-LEDs (405 nm) on different layers of carbon nanotube (CNT) patterns were fabricated by laser lift off (LLO), compared with the conventional lateral counterparts. The LLO threshold energy was reduced by CNTs layers. Although conventional lateral LEDs (LLEDs) exhibited highest external quantum efficiency (EQE) on 2CNTs pattern, the EQE of 3CNTs vertical LEDs (VLEDs) surpassed after LLO. The intrinsic physics mechanism, including: internal quantum efficiency (IQE), light extraction efficiency (LEE), Shockley-Read-Hall (SRH) recombination, radiative recombination and Auger effects, were analyzed by ‘ABC model’, Raman spectrum, X-ray Diffraction (XRD) and temperature dependence photoluminescence (TDPL). •Threshold of GaN laser lift off from CNT patterned sapphire substrate was reduced.•Material quality and residual stress of GaN thin film on CNT patterned sapphire after laser lift off were studied.•Quantum efficiency of vertical LEDs on CNT patterned sapphire was investigated by ‘ABC’ model.
ISSN:0022-2313
1872-7883
DOI:10.1016/j.jlumin.2021.117938