InGaN-based light-emitting diodes with an embedded conical air-voids structure

Huang, Yu-Chieh; Lin, Chia-Feng; Chen, Sy-Hann; Dai, Jing-Jie; Wang, Guei-Miao; Huang, Kun-Pin; Chen, Kuei-Ting; Hsu, Yi-Hsiang

doi:10.1364/oe.19.000a57

Cited by 20 publications

(10 citation statements)

References 20 publications

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“…Compared to the C-LED, which emits light only in the device region, the HSM-LED has a larger luminescence region, lighting up the area around the device, as shown in Figure (c). We also observed a similar result in our EL experiments (SI, Figure S3) and reference to confirm this phenomenon. , …”

Section: Analysis Of Light Extraction Efficiency In a Structure With ...supporting

confidence: 89%

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

Chen,

Lei,

Meng

et al. 2023

ACS Photonics

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This work demonstrates high-efficiency InGaN-based light-emitting diodes (HSM-LEDs) prepared on hexagonal 3D serpentine sapphire substrates. The 3D serpentine mask has a modulating effect on epitaxial lateral growth (ELOG), which can not only reduce the dislocation density (TDD) to 1.7 × 107 cm–2 without any high dislocation density (HDD) region but also induce the formation of a hexagonal pyramidal air-void array with an inclination angle of 65°. Compared to conventional LEDs, HSM-LEDs exhibit a 117% enhancement in EL output power at a current injection of 600 mA. This can be attributed to the improvement of crystal quality by modulated ELOG, the relief of in-plane stresses to mitigate the quantum-confined Stark effect (QCSE) through the weak connection of the epitaxial layer to the substrate, and the enhanced light extraction efficiency by an embedded air-void array. We confirmed the reduction of compressive stress from 0.94 GPa to 0.51 GPa in HSM-LEDs by Raman spectroscopy and investigated the effect of air voids on light extraction efficiency (LEE) experimentally and theoretically. Ray-tracing simulations show that the embedded pyramidal air voids can effectively re-extract the downward emitted light, and the pyramidal air voids with a 65° slant sidewall can improve the LEE by 71%.

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Section: Analysis Of Light Extraction Efficiency In a Structure With ...supporting

confidence: 89%

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

Chen,

Lei,

Meng

et al. 2023

ACS Photonics

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“…Seamless integration of embedded dielectric microstructures in III–V crystal growth is an active area of research due to its numerous important applications. Recent efforts include increased light extraction via air voids in the III-Nitrides, , site-control of quantum emitters, , embedded air holes to create 2D-slab and 3D photonic crystals to enhance emitters, , and, most commonly, dislocation blocking in metamorphic heteroepitaxy for low defect III–V growth. − From an epitaxial growth perspective, the primary challenge in embedding dielectric microstructures is achieving single-crystal high-quality planar coalescence, which requires the joining of two or more crystal fronts without forming defects and returning the growth front to the substrate orientation, commonly the (001) plane. Since the challenges are growth-based, investigation into planar coalescence focuses entirely around the methodologies of a specific crystal growth technique.…”

Section: Introductionmentioning

confidence: 99%

High-Quality GaAs Planar Coalescence over Embedded Dielectric Microstructures Using an All-MBE Approach

Ironside

Skipper

Leonard

et al. 2019

Crystal Growth & Design

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We demonstrate for the first time an entirely molecular beam epitaxy (MBE) approach to high-quality GaAs planar coalescence over embedded dielectric microstructures. Specifically, an all-MBE approach was achieved by developing a new two-stage growth process, merging the MBE growth regimes of III-flux modulated lateral epitaxial overgrowth (LEO) with self-ordered planarization of nonplanar substrates to produce highly selective planar coalescence specifically for embedding [010]-aligned silica gratings patterned on (001) substrates. The resulting planar coalescence returned a smooth (001) surface with surface roughness as low as 3 nm root-mean-square and photoluminescence (PL) equivalent to grating-free controls. In demonstrating high-quality GaAs coalescence, we also report for the first time an intentionally enhanced single InGaAs/GaAs/AlAs quantum well PL test structure seamlessly grown directly above embedded silica gratings, leading to a 1.4× enhancement in PL as a result of both Purcell and extraction enhancements corroborated by time-resolved PL studies. As a result, we provide a significant advance to the long-standing challenge of marrying high-quality semiconductor crystal growth with dielectric microstructures, unlocking several high-impact applications, such as enhanced quantum emitters and embedded metasurfaces for quantum information processing, and provide a pathway for all-MBE metamorphic III−V heteroepitaxy.

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“…These air voids can serve as distributed Bragg reflector in enhancing the light extraction efficiency (LEE) of LEDs. The TD annihilation around the air voids can result a highly crystalline GaN epilayer with reduced defect density [ 17 , 38 , 39 ].…”

Section: Resultsmentioning

confidence: 99%

Defect-selective-etched porous GaN as a buffer layer for high efficiency InGaN/GaN light-emitting diodes

Park¹,

Baek

Kim

et al. 2022

PLoS ONE

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Substrate-induced biaxial compressive stress and threading dislocations (TDs) have been recognized to severely impair the performance, stability, and reliability of InGaN/GaN light-emitting diodes (LEDs) for quite some time. In this study, a defect-selective-etched (DSE) porous GaN layer is fabricated employing electro-chemical etching and applied as a buffer layer for the development of InGaN/GaN LEDs with high quantum efficiency. Based on the analysis of photoluminescence and micro-Raman spectra, it has been revealed that the overgrown GaN epilayer on the DSE porous GaN has a relatively low TDs and relaxation of compressive stress in comparison to the conventional GaN epilayer. The remarkable improvement in the internal quantum efficiency of the InGaN/GaN LEDs is directly attributable to the strong radiative recombination in InGaN/GaN multi-quantum-wells caused by stress relaxation and TDs annihilation. Our findings indicate that the use of DSE porous GaN as a buffer layer may be a viable approach for producing crystalline GaN epilayers and high-performance LEDs.

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InGaN-based light-emitting diodes with an embedded conical air-voids structure

Cited by 20 publications

References 20 publications

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

Enhanced Performance of InGaN Light-Emitting Diodes via High-Quality GaN and Embedded Air Voids Grown on Hexagonal 3D Serpentine Mask Sapphire Substrates

High-Quality GaAs Planar Coalescence over Embedded Dielectric Microstructures Using an All-MBE Approach

Defect-selective-etched porous GaN as a buffer layer for high efficiency InGaN/GaN light-emitting diodes

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