Monolithic Light Reflector‐Nanowire Light Emitting Diodes

Ra, Yong–Ho; Lee, Cheul-Ro

doi:10.1002/admt.202000885

Cited by 7 publications

(7 citation statements)

References 47 publications

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“…The nanohole TiN mask was fabricated using the e-beam lithography technique, and it has a thickness of 12 nm. This thickness determines the diameter of the nanorod. − The photonic crystal effect shown in Figure can be achieved with better crystal quality by growing uniform nanorods from uniform patterning holes. Figure b depicts the array of nanorod structures fabricated by selective area growth.…”

Section: Resultsmentioning

confidence: 99%

Structural Engineering in a Microscale Laser Diode with InGaN Tunnel-Junction Nanorods

Kim

et al. 2023

ACS Photonics

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The development of next-generation pixels with a smaller size, lower power consumption, and higher luminance is required for VR and XR display applications. Here, we showed the selective area epitaxial growth of a novel GaN nanorod-based LD tunnel-junction structure incorporating a photonic crystal effect. The nanorod based DBR-free GaN LD structure with the photonic crystal effect has demonstrated to be a surface-emitting laser diode that emits light in a vertical direction. The fabricated GaN nanorod laser diode device showed lasing performance at a wavelength of 502 nm with a full width at half-maximum of 0.98 nm. Moreover, a low turn-on voltage of ∼2.49 V was achieved by the novel tunnel junction-based n-GaN to metal contact structure, and as a result, the reduction in the light efficiency was significantly improved, even during a long operating time. Such a unique 5 μm × 5 μm nanorod LD device is not only useful for future display pixels that need to have high brightness and ultrahigh definition, but also opens up a new platform of nano-optoelectronic devices in the future.

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Section: Resultsmentioning

confidence: 99%

Structural Engineering in a Microscale Laser Diode with InGaN Tunnel-Junction Nanorods

Kim

et al. 2023

ACS Photonics

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“…To enhance the LEE, a few LED structures with metallic reflectors such as Ag, Au were demonstrated previously [31][32][33]. In particular, the Al reflector in nanostructure LED showed that can greatly improve the LEE [34]. For electrode, Al could be a best candidate as it exhibits high reflectance over a wide wavelength range [35,36] and high electrical conductivity.…”

Section: Pj-013607-2022mentioning

confidence: 99%

Sub-Micron Monolithic Full-Color Nanorod LEDs on A Single Substrate

Kim

et al. 2023

IEEE Photonics J.

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The extended reality (XR) display, including augmented reality (AR) and virtual reality (VR), requires ultrahigh-resolution and high-luminance pixel technology. GaNbased micro-LEDs are the most promising for high-density pixel applications. However, it is necessary to simultaneously fabricate full-color R/G/B emitters on a single substrate. Moreover, the efficiency droop at long wavelengths with high-indium InGaN still remains a challenge. The InGaN nanorod has the potential to realize monolithic R/G/B LEDs on a single substrate, and the Al reflector has a light reflectance that can dramatically improve light extraction efficiency. Here, we designed sub-micron monolithic full-color R/G/B nanorod LEDs with an Al core-shell reflector on single chip. The optimal structures for light confinement and vertical light extraction by single InGaN nanorod R/G/B LED structures were identified. The single nanorod with Al core-shell structure dramatically increased the light extraction efficiency, and showed an improvement of more than 20%, especially in the red wavelength. As a result, by introducing a longlength nanorod structure, we have successfully designed a new submicron pixel with full-color R/G/B LEDs operating within 1 x 1 μm2 size. This unique design will be a key factor in enabling the next generation of AR and VR displays that require ultra-small and compact pixels.

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“…In 2021, Ra et al unveiled a strong light efficiency enhancement of nanowire µ-LED at 550 nm by the adoption of an Al mirror to break the green gap limit of GaN emitting devices. [93] The MBE epitaxially grown high-quality Al mirror was adopted to form a smooth mirror surface. In addition, the radiative pattern of the LED was directional along the vertical surface direction with a small radiation angle of 15°.…”

Section: Hybrid Dbr With Metal Reflectorsmentioning

confidence: 99%

Progress of GaN‐Based Optoelectronic Devices Integrated with Optical Resonances

Zhao

Liu

Wang

2022

Small

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are even smaller, only a few MHz, which are far away from the requirement of fast and large data wireless transmission for VLC. [5] To enhance the data transmission rates, complex modulation schemes and/ or equalization have to be utilized, which, however, hinder the further developments and applications. In addition, Si-based optoelectronic devices, like Si PDs, a bluefiltering technology are still used currently for shorter wavelength visible light detection, which suffers from complexity and low light transmittance. Furthermore, considering the development and mature application of GaN-based devices, there is a trend to realize the multifunctional single chip integration. However, the relative low coupling efficiency in the GaNbased optoelectronic devices still cannot meet the requirements. In this case, it is important to develop novel GaN-based optoelectronic devices with superior performances as alternative for miniaturization, simplification, and integration. To solve these problems, the concept of incorporating GaN-based devices with exotic optical resonances has been proposed. [5] Surface plasmons (SPs), microcavities, such as whispering gallery modes (WGMs) and distributed Bragg reflectors (DBR) are common optical resonant structures to improve the performances of GaN-based devices. [6][7][8][9] SPs are intrinsic electromagnetic modes excited at the metal-dielectric interfaces, accompanied with the collective oscillation behaviors of free electrons on the metal-side surfaces. [10] Giant electric field enhancement generates at the interface with exponentially decay along the perpendicular direction. Inside the GaN-based devices, the excitation of SPs can greatly enhance the density of states of the electron-hole pairs and improve the competitiveness of the radiative recombination to the non-radiative recombination. [11] It has also been demonstrated tremendously in early works that using SPs enables a path to break the optical diffraction limit of the semiconductor lasers and boost the light-matter coupling intensities in subwavelength dimensions. [11][12][13][14][15][16][17] In addition, GaN-based microcavities, such as photonics crystals, DBR, and micro disks, can confine and manipulate light. [18][19][20] By matching one or more dimensions of the cavities to the wavelength of the confined light, exotic effects can be produced, such as enhanced luminescence, directional emission, low-threshold lasing, etc. When light illuminates microcavities, the confined electron-hole pairs interact with the cavity photons. Their interaction rate relative to the average Being direct wide bandgap, III-nitride (III-N) semiconductors have many applications in optoelectronics, including light-emitting diodes, lasers, detectors, photocatalysis, etc. Incorporation of III-N semiconductors with high-efficiency optical resonances including surface plasmons, distributed Bragg reflectors and micro cavities, has attracted considerable interests for upgrading their performance, which can not only reveal the new coupling mechanism...

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Monolithic Light Reflector‐Nanowire Light Emitting Diodes

Cited by 7 publications

References 47 publications

Structural Engineering in a Microscale Laser Diode with InGaN Tunnel-Junction Nanorods

Structural Engineering in a Microscale Laser Diode with InGaN Tunnel-Junction Nanorods

Sub-Micron Monolithic Full-Color Nanorod LEDs on A Single Substrate

Progress of GaN‐Based Optoelectronic Devices Integrated with Optical Resonances

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