Three dimensional simulation on the transport and quantum efficiency of UVC-LEDs with random alloy fluctuations

Hung-Hsiang Chen; James S. Speck; Claude Weisbuch; Yuh-Renn Wu

doi:10.1063/1.5051081

Three dimensional simulation on the transport and quantum efficiency of UVC-LEDs with random alloy fluctuations

Hung-Hsiang Chen, James S. Speck, Claude Weisbuch, Yuh-Renn Wu

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

27 Scopus citations

Abstract

The active regions of ultraviolet light emitting diodes (UVLEDs) for UVB and ultra-violet band C wavelengths are composed of AlGaN alloy quantum barriers (QBs) and quantum wells (QWs). The use of alloy QBs and QWs facilitates the formation of percolative paths for carrier injection but also decreases carrier confinement within the QWs. We applied the recently developed Localization Landscape (LL) theory for a full 3D simulation of the LEDs. LL theory describes the effective quantum potential of the quantum states for electrons and holes in a random disordered system with a high computational speed. The results show that the potential fluctuations in the n-AlGaN buffer layer, QWs, and QBs provide percolative paths for carrier injection into the top (p-side) QW. Several properties due to compositional disorder are observed: (1) The peak internal quantum efficiency is larger when disorder is present, due to carrier localization, than for a simulation without fluctuations. (2) The droop is larger mainly due to poor hole injection and weaker blocking ability of the electron blocking layer caused by the fluctuating potentials. (3) Carriers are less confined in the QW and extend into the QBs due to the alloy potential fluctuations. The wave function extension into the QBs enhances TM emission as shown from a k·p simulation of wave-functions admixture, which should then lead to poor light extraction.

Original language	English (US)
Pages (from-to)	153504
Journal	Applied Physics Letters
Volume	113
Issue number	15
DOIs	https://doi.org/10.1063/1.5051081
State	Published - Oct 11 2018
Externally published	Yes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was funded by Ministry of Science and Technology (MOST) in Taiwan under Grants No. MOST 105-2221-E-002-098-MY3 and MOST 104-2923-E-002-004-MY3 and by the French National Research Agency (ANR) under Grant No. ANR-14-CE05-0048-01. Additional support for JSS was provided by the KACST-KAUST-UCSB Solid State Lighting Program. Special thanks to Marcel Filoche (Ecole Polytechnique) for many useful discussions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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@article{b7c80b11fa4042519c0a64e5283822da,

title = "Three dimensional simulation on the transport and quantum efficiency of UVC-LEDs with random alloy fluctuations",

abstract = "The active regions of ultraviolet light emitting diodes (UVLEDs) for UVB and ultra-violet band C wavelengths are composed of AlGaN alloy quantum barriers (QBs) and quantum wells (QWs). The use of alloy QBs and QWs facilitates the formation of percolative paths for carrier injection but also decreases carrier confinement within the QWs. We applied the recently developed Localization Landscape (LL) theory for a full 3D simulation of the LEDs. LL theory describes the effective quantum potential of the quantum states for electrons and holes in a random disordered system with a high computational speed. The results show that the potential fluctuations in the n-AlGaN buffer layer, QWs, and QBs provide percolative paths for carrier injection into the top (p-side) QW. Several properties due to compositional disorder are observed: (1) The peak internal quantum efficiency is larger when disorder is present, due to carrier localization, than for a simulation without fluctuations. (2) The droop is larger mainly due to poor hole injection and weaker blocking ability of the electron blocking layer caused by the fluctuating potentials. (3) Carriers are less confined in the QW and extend into the QBs due to the alloy potential fluctuations. The wave function extension into the QBs enhances TM emission as shown from a k·p simulation of wave-functions admixture, which should then lead to poor light extraction.",

author = "Hung-Hsiang Chen and Speck, {James S.} and Claude Weisbuch and Yuh-Renn Wu",

note = "KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: This work was funded by Ministry of Science and Technology (MOST) in Taiwan under Grants No. MOST 105-2221-E-002-098-MY3 and MOST 104-2923-E-002-004-MY3 and by the French National Research Agency (ANR) under Grant No. ANR-14-CE05-0048-01. Additional support for JSS was provided by the KACST-KAUST-UCSB Solid State Lighting Program. Special thanks to Marcel Filoche (Ecole Polytechnique) for many useful discussions. This publication acknowledges KAUST support, but has no KAUST affiliated authors.",

year = "2018",

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doi = "10.1063/1.5051081",

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journal = "Applied Physics Letters",

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T1 - Three dimensional simulation on the transport and quantum efficiency of UVC-LEDs with random alloy fluctuations

AU - Chen, Hung-Hsiang

AU - Speck, James S.

AU - Weisbuch, Claude

AU - Wu, Yuh-Renn

N1 - KAUST Repository Item: Exported on 2020-10-01 Acknowledgements: This work was funded by Ministry of Science and Technology (MOST) in Taiwan under Grants No. MOST 105-2221-E-002-098-MY3 and MOST 104-2923-E-002-004-MY3 and by the French National Research Agency (ANR) under Grant No. ANR-14-CE05-0048-01. Additional support for JSS was provided by the KACST-KAUST-UCSB Solid State Lighting Program. Special thanks to Marcel Filoche (Ecole Polytechnique) for many useful discussions. This publication acknowledges KAUST support, but has no KAUST affiliated authors.

PY - 2018/10/11

Y1 - 2018/10/11

N2 - The active regions of ultraviolet light emitting diodes (UVLEDs) for UVB and ultra-violet band C wavelengths are composed of AlGaN alloy quantum barriers (QBs) and quantum wells (QWs). The use of alloy QBs and QWs facilitates the formation of percolative paths for carrier injection but also decreases carrier confinement within the QWs. We applied the recently developed Localization Landscape (LL) theory for a full 3D simulation of the LEDs. LL theory describes the effective quantum potential of the quantum states for electrons and holes in a random disordered system with a high computational speed. The results show that the potential fluctuations in the n-AlGaN buffer layer, QWs, and QBs provide percolative paths for carrier injection into the top (p-side) QW. Several properties due to compositional disorder are observed: (1) The peak internal quantum efficiency is larger when disorder is present, due to carrier localization, than for a simulation without fluctuations. (2) The droop is larger mainly due to poor hole injection and weaker blocking ability of the electron blocking layer caused by the fluctuating potentials. (3) Carriers are less confined in the QW and extend into the QBs due to the alloy potential fluctuations. The wave function extension into the QBs enhances TM emission as shown from a k·p simulation of wave-functions admixture, which should then lead to poor light extraction.

AB - The active regions of ultraviolet light emitting diodes (UVLEDs) for UVB and ultra-violet band C wavelengths are composed of AlGaN alloy quantum barriers (QBs) and quantum wells (QWs). The use of alloy QBs and QWs facilitates the formation of percolative paths for carrier injection but also decreases carrier confinement within the QWs. We applied the recently developed Localization Landscape (LL) theory for a full 3D simulation of the LEDs. LL theory describes the effective quantum potential of the quantum states for electrons and holes in a random disordered system with a high computational speed. The results show that the potential fluctuations in the n-AlGaN buffer layer, QWs, and QBs provide percolative paths for carrier injection into the top (p-side) QW. Several properties due to compositional disorder are observed: (1) The peak internal quantum efficiency is larger when disorder is present, due to carrier localization, than for a simulation without fluctuations. (2) The droop is larger mainly due to poor hole injection and weaker blocking ability of the electron blocking layer caused by the fluctuating potentials. (3) Carriers are less confined in the QW and extend into the QBs due to the alloy potential fluctuations. The wave function extension into the QBs enhances TM emission as shown from a k·p simulation of wave-functions admixture, which should then lead to poor light extraction.

UR - http://hdl.handle.net/10754/629811

UR - http://aip.scitation.org/doi/10.1063/1.5051081

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U2 - 10.1063/1.5051081

DO - 10.1063/1.5051081

M3 - Article

SN - 0003-6951

VL - 113

SP - 153504

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 15

ER -

Three dimensional simulation on the transport and quantum efficiency of UVC-LEDs with random alloy fluctuations

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