Efficiency Models for GaN-Based Light-Emitting Diodes: Status and Challenges

Piprek, Joachim

doi:10.3390/ma13225174

Cited by 42 publications

(26 citation statements)

References 142 publications

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“…The threshold current for lasing operation is mainly controlled by the QW Auger recombination coefficient C for which widely scattered values are reported (Piprek 2020b). Within the reported range we find that C = 6.1  10 -30 cm 6 /s delivers good agreement with the measurement (see below).…”

Section: Models and Materials Parameterssupporting

confidence: 80%

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GaN-based bipolar cascade lasers with 25 nm wide quantum wells

Piprek¹,

Muzioł

Siekacz

et al. 2022

Opt Quant Electron

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Utilizing self-consistent numerical simulation in good agreement with measurements, we analyze internal device physics, performance limitations, and optimization options for a unique laser design with multiple active regions separated by tunnel junctions, featuring surprisingly wide InGaN quantum wells. Contrary to common assumptions, these quantum wells are revealed to allow for perfect screening of the strong built-in polarization field, while optical gain is provided by higher quantum levels. However, internal absorption, low p-cladding conductivity, and self-heating are shown to strongly limit the laser performance.

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Section: Models and Materials Parameterssupporting

confidence: 80%

“…Intense worldwide efforts have been focusing on efficiency improvements of GaN-based light emitters (Piprek 2020b). Among the most intriguing proposals is the cascading of multiple active regions with tunnel junctions in between.…”

Section: Introductionmentioning

confidence: 99%

GaN-based bipolar cascade lasers with 25 nm wide quantum wells

Piprek¹,

Muzioł

Siekacz

et al. 2022

Opt Quant Electron

Self Cite

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“…[ 1,2 ] In a DHJ the active region (AR), e.g., a multi‐quantum well (MQW) stack, is sandwiched between p‐ and n‐type charge injection layers, where electrons and holes enter or exit the AR from opposite directions. This configuration has satisfied the needs of most optoelectronic devices for several decades, but it has limitations for many emerging applications where extremely efficient current spreading [ 3–5 ] or unconventional geometries are required. [ 6–10 ] Examples of these applications include not only light emitters such as high‐power blue and ultraviolet vertical III‐nitride LEDs [ 11–17 ] and LEDs for electroluminescent cooling, [ 18 ] but also current collection devices such as carrier‐selective GaAs solar cells.…”

Section: Introductionmentioning

confidence: 99%

Back‐Contacted Carrier Injection for Scalable GaN Light Emitters

Kim

Kauppinen

Radevici

et al. 2021

Physica Status Solidi (a)

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It has recently been proposed that back‐contacted III–V light‐emitting diodes (LEDs) could offer improved current spreading as compared to conventional mesa or double side contacted structures. This has inspired also experimental efforts to realize such structures, but fabrication methods for them have not yet been fully established. Herein, the use of unintentionally doped and partially carrier‐selective contacts (SC) is studied to realize back‐contacted indium gallium nitride (InGaN) LEDs. The sharp electroluminescence peak at 439 nm from the multiquantum well stack demonstrates that the approach allows fabricating back‐contacted InGaN LEDs without intentionally doped n‐GaN layers and without inflicting damage in the active region, often observed in alternative approaches relying on lateral doping and the use of high energy particles during fabrication. The samples are fabricated on a finger configuration with several finger widths between 1 and 20 μm. It is observed that the emission spreads most uniformly throughout the structure for fingers with the width of 5 μm. As shown by the simulations, with improved contact resistances, the structures reported herein could enable fabricating back‐contacted LEDs with unity injection efficiency and improved current spreading, offering a path toward large‐area LEDs without contact shading even in materials where n‐doping is elusive.

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“…1.2-1.5 kV devices are essential to medical equipments such as positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging (MRI) scanners for rectifier purposes. Devices in these instruments also require having lower leakage and faster recoveries [12]. Automotive industry shows high interest for DC to AC power conversions to operate electric motors in hybrid vehicles, and for AC to DC power conversions of traction rectifiers in electric trains, metros, and trams [13].…”

Section: Introductionmentioning

confidence: 99%

Design and development of 1.5 kV vertical GaN pn diodes on HVPE substrate

Talesara

Zhang

Chen

et al. 2021

Journal of Materials Research

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We report the design and development of vertical 1.5 kV GaN p-n diodes that consists of an 8 μm drift layer and a thin p-GaN/p + -GaN layer grown by metal-organic chemical vapor deposition (MOCVD) on a hydride vapor phase epitaxy (HVPE) synthesized GaN substrate. The drift layer has a low doping concentration of ∼9 × 10 15 cm −3 and electron mobility ~ 1200 cm 2 /Vs at room temperature. The fabricated devices with an optimized guard ring design as edge termination exhibit a breakdown voltage of > 1.5 kV with specific on-resistance of ~ 1.5 mΩ cm 2 . The breakdown efficiency of these diodes is over 72% when compared to ideal analytical calculations and over 90% with respect to numerical simulations. Temperature-dependent measurements show that the devices have a positive temperature coefficient suggesting the avalanche breakdown mechanism. These results suggest that these MOCVD grown vertical GaN-on-GaN (HVPE) p-n diodes are promising for low-mid range voltage power switching applications.

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Efficiency Models for GaN-Based Light-Emitting Diodes: Status and Challenges

Cited by 42 publications

References 142 publications

GaN-based bipolar cascade lasers with 25 nm wide quantum wells

GaN-based bipolar cascade lasers with 25 nm wide quantum wells

Back‐Contacted Carrier Injection for Scalable GaN Light Emitters

Design and development of 1.5 kV vertical GaN pn diodes on HVPE substrate

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