Demonstration of novel high-efficiency blue LEDs on silicon substrates

Kimura, Shuichi; Yoshida, Hisashi; Ito, Toshihide; Okada, Aoi; Uesugi, Kenjiro; Nunoue, Shinya

doi:10.1117/2.1201603.006402

Cited by 2 publications

(2 citation statements)

References 9 publications

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“…One approach for higher efficiency longer wavelength InGaN LEDs that has produced record efficiencies at green gap wavelengths is the use of AlGaN interlayers in the multiple quantum well (MQW) active layer . This is most interesting in the green and red because of demonstrated record external quantum efficiencies of ≈25% at ≈550 nm and ≈2.5% at ≈608 nm.…”

Section: Challenges and Solutionsmentioning

confidence: 99%

III‐Nitride Micro‐LEDs for Efficient Emissive Displays

Wierer

Tansu

2019

Laser & Photonics Reviews

112

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Emissive displays based on light‐emitting diodes (LEDs), with high pixel density, luminance, efficiency, and large color gamut, are of great interest for applications such as watches, phones, and virtual displays. The high pixel density requirements of some emissive displays require a particular class of LEDs that are sub‐20‐micrometers in length, called micro‐LEDs. While state‐of‐the‐art emissive displays incorporate organic LEDs, an alternative is inorganic III‐nitride LEDs with potential reliability and efficiency benefits. Here we explore the performance, challenges, and prospective outcomes for III‐nitride micro‐LEDs to produce efficient emissive displays and provide insight to advance this technology. Calculations are performed to determine the operating points for the micro‐LEDs and the efficiency of the overall emissive display. It is shown that III‐nitride micro‐LEDs suffer from some of the same problems as their larger‐sized solid‐state lighting LED cousins; however, the operating conditions of micro‐LEDs can result in different challenges and research efforts. These challenges include improving efficiency at low current densities; improving the efficiency of longer wavelength (green and red) LEDs; and creating device designs that can overcome low coupling efficiency, high surface recombination, and display assembly difficulties.

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Section: Challenges and Solutionsmentioning

confidence: 99%

III‐Nitride Micro‐LEDs for Efficient Emissive Displays

Wierer

Tansu

2019

Laser & Photonics Reviews

112

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“…[3][4][5][6][7][8] However, despite all these advantages and worldwide research activities, the performance of NW based light-emitting diodes (LEDs) lags behind that of their state-of-theart two-dimensional counterparts fabricated on Al 2 O 3 and Si substrates, which nowadays exhibit wall-plug and external quantum efficiencies above 80 % in the blue spectral range. 9,10 The inferior performance of NW-based LEDs is mainly caused by the limitations and complexities inherent to their formation using bottomup methods. Particularly, the nonideal growth conditions often required to promote either uniaxial or radial growth may favor the incorporation of higher concentrations of impurities and defects.…”

Section: Introductionmentioning

confidence: 99%

Top-down fabrication of ordered arrays of GaN nanowires by selective area sublimation

et al. 2019

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We demonstrate the top-down fabrication of ordered arrays of GaN nanowires by selective area sublimation of pre-patterned GaN(0001) layers grown by hydride vapor phase epitaxy on Al 2 O 3 . Arrays with nanowire diameters and spacings ranging from 50 to 90 nm and 0.1 to 0.7 µm, respectively, are simultaneously produced under identical conditions. The sublimation process, carried out under high vacuum conditions, is analyzed in situ by reflection high-energy electron diffraction and line-of-sight quadrupole mass spectromety. During the sublimation process, the GaN(0001) surface vanishes, giving way to the formation of semi-polar {1103} facets which decompose congruently following an Arrhenius temperature dependence with an activation energy of (3.54 ± 0.07) eV and an exponential prefactor of 1.58 × 10 31 atoms cm −2 s −1 . The analysis of the samples by low-temperature cathodoluminescence spectroscopy reveals that, in contrast to dry etching, the sublimation process does not introduce nonradiative recombination centers at the nanowire sidewalls. This technique is suitable for the top-down fabrication of a variety of ordered nanostructures, and could possibly be extended to other material systems with similar crystallographic properties such as ZnO. † Electronic Supplementary Information (ESI) available: Analysis of GaN facets formed during thermal sublimation by reflection high-energy electron diffraction. See

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Demonstration of novel high-efficiency blue LEDs on silicon substrates

Abstract: Metal organic chemical vapor deposition is used to grow aluminum gallium nitride interlayers within indium gallium nitride/gallium nitride multi-quantum well structures on silicon substrates.

Cited by 2 publications

References 9 publications

III‐Nitride Micro‐LEDs for Efficient Emissive Displays

III‐Nitride Micro‐LEDs for Efficient Emissive Displays

Top-down fabrication of ordered arrays of GaN nanowires by selective area sublimation

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