Integration of GaN light-emitting diodes with a-Si:H thin-film transistors for flexible displays

Asad, Mohsen; Li, Qing; Lee, Czang-Ho; Sachdev, Manoj; Wong, William S.

doi:10.1088/1361-6528/ab1a5e

Cited by 20 publications

(10 citation statements)

References 18 publications

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“…Given LLO is able to take off the rigid sapphire substrate, a wide range of flexible LED display devices can be enabled. [42,47,51,131] In rare cases, no handling carrier was used for LLO. [130] As an example, Choi et al [130] used this concept to develop freestanding, naturally bended Micro-LED stripes for curved displays (Figure 10c).…”

Section: Micro-led Transfer By Llomentioning

confidence: 99%

Laser‐Based Micro/Nano‐Processing Techniques for Microscale LEDs and Full‐Color Displays

Gong

2022

Adv Materials Technologies

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Micro light‐emitting diode (Micro‐LED) display is an emerging display technology thanks to its high brightness, fast switching speed, and low power consumption. The commercialization of this technique is being explored by developing advanced processing techniques on an industrial scale. Recent ground‐breaking advances in the manufacture of Micro‐LEDs are mainly based on powerful laser micro/nano‐processing techniques with the unique ability to fabricate materials, structures and devices with the advantages of non‐contacting processing, high efficiency, adjustable coverage from micro‐ to macroscale and the compatibility with organic and inorganic materials. This paper categorizes, reviews and analyzes the main challenges and technical solutions in the Micro‐LED displays by various laser manufacturing processes, covering chip dicing, geometry shaping, laser annealing, laser lift‐off (LLO), laser‐based Micro‐LED transfer, laser‐assist bonding (LAB) and laser repair. The fundamental principles of these techniques are discussed along with their basic mechanisms, followed by an exploration of the latest progress in the field. Finally, a detailed analysis of the advantages and disadvantages of these techniques is given, and the future research directions of laser techniques in Micro‐LED display are discussed.

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Section: Micro-led Transfer By Llomentioning

confidence: 99%

Laser‐Based Micro/Nano‐Processing Techniques for Microscale LEDs and Full‐Color Displays

Gong

2022

Adv Materials Technologies

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“…Especially, there have been notably increasing reports on III-nitride semiconductor based micro-LEDs, since they exhibit high efficiency and brightness, and above all, they can cover all the spectral range that present display requires (e.g. sRGB), in help with color conversion technique 7 – 9 .…”

Section: Introductionmentioning

confidence: 99%

Influence of wafer quality on chip size-dependent efficiency variation in blue and green micro light-emitting diodes

Woo

Song

Lee

et al. 2022

Sci Rep

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We propose a key factor associated with both surface recombination velocity and radiative efficiency of an LED to estimate its chip size-dependent radiative efficiencies. The validity of the suggested factor is verified through experimental comparison between various LED wafers. Efficiencies of micro-LEDs from a blue and two green LED wafers are examined by temperature-dependent photoluminescence experiments. Surface recombination velocities are extracted from chip size dependent time-resolved PL results. Possible explanations on the reason why two green wafers show different properties are also given. With the suggested factor, we can provide more accurate prediction on the chip size-dependent efficiency of an LED wafer.

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“…GaN-based micro-scale light-emitting diodes (micro-LEDs) are emerging as one of the most promising technologies for the next-generation flat-panel displays (FPDs) by providing a broad ultraviolet-to-red spectral range. − Recently, vertical micro-LED structures with a reflective metal coated backside has proved to be one of the best candidates for FPDs over lateral structures, where most of the generated photons are trapped inside the device in the latter structure due to a small critical angle for internal reflection (θ c = 25°). − As a result, a strong micro-cavity effect can be observed, which reduces the light coupling out of the LED. − One approach to minimize the micro-cavity resonance is to create a thinner LED structure, but this design results in low-light intensity because the active region is closer to the highly defective substrate/diode interface, resulting in a high density of threading dislocations propagating through the device active region . Detaching the substrate allows the removal of this defective region through a backside etching process .…”

Section: Introductionmentioning

confidence: 99%

Enhanced Surface-Emitting Vertical InGaN Light-Emitting Diodes by Self-Aligned Sidewall Electrodes and Optical Cavity Length Modulation

Asad

Sachdev

et al. 2021

ACS Appl. Electron. Mater.

Self Cite

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A technique to enhance the light extraction of InGaN-based micro-light-emitting diodes (LEDs) using an etchback and a self-aligned sidewall electrode structure was demonstrated. By removing the sapphire substrate, the backside of the micro-LEDs was selectively processed to remove the highly defective backside and allowed passivation of the LED sidewalls. The etch-back process enhanced the light coupling of photons emitting through the top p-contact by 2×. An Al n-contact, surrounding the passivated LED structure, was used to deplete carriers away from the interface defects along the LED sidewalls when the diode is forward biased, minimizing carrier recombination and reducing the leakage current by 10×. This structure effectively reduced contact series resistance from 0.12 to 5.6 × 10 −4 Ω. Optically, the LEDs showed a light extraction efficiency improvement by >200% and the combination of optical and electrical enhancements resulted in a >400% increase in the electroluminescence efficiency.

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Integration of GaN light-emitting diodes with a-Si:H thin-film transistors for flexible displays

Cited by 20 publications

References 18 publications

Laser‐Based Micro/Nano‐Processing Techniques for Microscale LEDs and Full‐Color Displays

Laser‐Based Micro/Nano‐Processing Techniques for Microscale LEDs and Full‐Color Displays

Influence of wafer quality on chip size-dependent efficiency variation in blue and green micro light-emitting diodes

Enhanced Surface-Emitting Vertical InGaN Light-Emitting Diodes by Self-Aligned Sidewall Electrodes and Optical Cavity Length Modulation

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