High‐Efficiency, High‐Power AlGaInP Thin‐Film LEDs with Micron‐Sized Truncated Cones as Light‐Extraction Structures

Wang, Xue‐Lun; Kumagai, Naoto; Hao, Guo-Dong

doi:10.1002/pssa.201700562

Cited by 5 publications

(2 citation statements)

References 27 publications

(35 reference statements)

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“…The laterally-emitted light causes severe optical cross-talk between adjacent pixels in highresolution displays, thus reducing the resolution and brightness of a µLED display [4,7]. To narrow the emission angle of a µLED, we recently proposed a directional µLED based on the coupling effect of evanescent waves in a sub-wavelengthsized truncated cone structure [8][9][10][11][12]. In this device, a minute active region with lateral dimensions much smaller than the emission wavelength was buried at the center of the truncated cone.…”

Section: Introductionmentioning

confidence: 99%

High-quality nanodisk of InGaN/GaN MQWs fabricated by neutral-beam-etching and GaN regrowth: towards directional micro-LED in top-down structure

Zhang

Takahashi

Ohori

et al. 2020

Semicond. Sci. Technol.

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A nanodisk array of blue InGaN/GaN multiple quantum wells was made using neutral beam etching (NBE) followed by GaN regrowth. The NBE-fabricated nanodisk presented a vertical and highly smooth sidewall surface where the InGaN well layers were easily distinguished even with a scanning electron microscope. A high interface quality without any voids or obvious defects was obtained between the nanodisk and the regrown-GaN layer. The nanodisk after regrowth presented a smaller blueshift of photoluminescence emission energy (12 meV) and a substantially higher and almost constant internal quantum efficiency of ~50% over three orders of magnitude of excitation laser power when compared to the nanodisk before regrowth. This study shows that the process of NBE nanodisk etching followed by GaN regrowth represents a promising step forward in the development of truncated cone-shaped directional micro-LEDs with a buried active region in a top-down structure.

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Section: Introductionmentioning

confidence: 99%

High-quality nanodisk of InGaN/GaN MQWs fabricated by neutral-beam-etching and GaN regrowth: towards directional micro-LED in top-down structure

Zhang

Takahashi

Ohori

et al. 2020

Semicond. Sci. Technol.

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“…Because UV LEDs lack a transparent current-spreading layer, researchers have no choice but to employ a bulk flip-chip (FC) LED architecture to spread the current over p-GaN/p-AlGaN. , TFFC LED architectures were successfully developed in visible LEDs − to improve the LEE and brightness; however, TFFC AlGaN LED technology − is still largely unexplored despite having higher brightness and better LEE than most bulk FC LED, especially for transverse-magnetic (TM) polarized emission …”

mentioning

confidence: 99%

AlGaN Deep-Ultraviolet Light-Emitting Diodes Grown on SiC Substrates

SaifAddin¹,

Almogbel

Zollner³

et al. 2020

ACS Photonics

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The disinfection industry would greatly benefit from efficient, robust, high-power deep-ultraviolet light-emitting diodes (UV–C LEDs). However, the performance of UV–C AlGaN LEDs is limited by poor light-extraction efficiency (LEE) and the presence of a large density of threading dislocations. We demonstrate high power AlGaN LEDs grown on SiC with high LEE and low threading dislocation density. We employ a crack-free AlN buffer layer with low threading dislocation density and a technique to fabricate thin-film UV LEDs by removing the SiC substrate, with a highly selective SF6 etch. The LEDs (278 nm) have a turn-on voltage of 4.3 V and a CW power of 8 mW (82 mW/mm2) and external quantum efficiency (EQE) of 1.8% at 95 mA. KOH submicron roughening of the AlN surface (nitrogen-polar) and improved p-contact reflectivity are found to be effective in improving the LEE of UV light. We estimate the improved LEE by semiempirical calculations to be 33% (without encapsulation). This work establishes UV LEDs grown on SiC substrates as a viable architecture to large-area, high-brightness, and high-power UV LEDs.

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III-Nitride Nanostructures for High Efficiency Micro-LEDs and Ultraviolet Optoelectronics

Pandey

2022

IEEE J. Quantum Electron.

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High‐Efficiency, High‐Power AlGaInP Thin‐Film LEDs with Micron‐Sized Truncated Cones as Light‐Extraction Structures

Cited by 5 publications

References 27 publications

High-quality nanodisk of InGaN/GaN MQWs fabricated by neutral-beam-etching and GaN regrowth: towards directional micro-LED in top-down structure

High-quality nanodisk of InGaN/GaN MQWs fabricated by neutral-beam-etching and GaN regrowth: towards directional micro-LED in top-down structure

AlGaN Deep-Ultraviolet Light-Emitting Diodes Grown on SiC Substrates

III-Nitride Nanostructures for High Efficiency Micro-LEDs and Ultraviolet Optoelectronics

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