Size-Dependent Bandwidth of Semipolar ( $11\overline {2}2$ ) Light-Emitting-Diodes

Haemmer, M.; Roycroft, B.; Akhter, Mahbub; Dinh, Duc V.; Quan, Zhiheng; Zhao, Jie; Parbrook, P. J.; Corbett, Brian

doi:10.1109/lpt.2018.2794444

Cited by 37 publications

(37 citation statements)

References 18 publications

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“…[ 137 ] Modulation performances of ≈1 GHz have been demonstrated [ 138 ] and comparative studies on polar/semipolar devices confirm a bandwidth improvement using this approach. [ 139 ] A calibrated modulation bandwidth of 1.5 GHz has also been shown for a nonpolar micro‐LED. [ 140 ] Such high values show the potential of non‐c‐plane micro‐LEDs.…”

Section: Visible Light Communication (Vlc)mentioning

confidence: 99%

Micro‐Light Emitting Diode: From Chips to Applications

Parbrook

Corbett

Han

et al. 2021

Laser & Photonics Reviews

157

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Typical light‐emitting diodes (LEDs) have a form factor >(300 × 300) µm2. Such LEDs are commercially mature in illumination and ultralarge displays. However, recent LED research includes shrinking individual LED sizes from side lengths >300 µm to values <100 µm, leading to devices called micro‐LEDs. Their advent creates a number of exciting new application spaces. Here, a review of the principles and applications of micro‐LED technology is presented. In particular, the implications of reduced LED size in necessitating mitigation strategies for nonradiative device edge damage as well as the potential for higher drive current densities are discussed. The opportunities to integrate micro‐LEDs with electronics, and into large‐scale arrays, allow pixel addressable scalable integrated displays, while the small micro‐LED size is ideal for high‐speed modulation for visible light communication, and for integration into biological systems as part of optogenetic therapies.

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Section: Visible Light Communication (Vlc)mentioning

confidence: 99%

Micro‐Light Emitting Diode: From Chips to Applications

Parbrook

Corbett

Han

et al. 2021

Laser & Photonics Reviews

157

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“…For semipolar LEDs, the internal fields are reduced depending on the angle of inclination with respect to the c-axis. Epitaxial growth on (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) shows a polarization field of almost zero. In addition, the incorporated indium atoms have lower repulsive interactions than those on nonpolar or polar surfaces, indicating that semipolar (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) GaN surfaces can accommodate more indium atoms than nonpolar or polar surfaces, making them more suitable for achieving longer wavelength emitters.…”

Section: Semi/nonpolar Leds Epitaxial Growthmentioning

confidence: 99%

“…Epitaxial growth on (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) shows a polarization field of almost zero. In addition, the incorporated indium atoms have lower repulsive interactions than those on nonpolar or polar surfaces, indicating that semipolar (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) GaN surfaces can accommodate more indium atoms than nonpolar or polar surfaces, making them more suitable for achieving longer wavelength emitters. [10] According to the traditional ABC model, carrier recombination rate equation R(n) can be expressed as…”

Section: Semi/nonpolar Leds Epitaxial Growthmentioning

confidence: 99%

“…Therefore, compared with polar LEDs, semi/nonpolar LEDs have a higher probability of electron-hole wave function overlap, resulting in higher bandwidth and luminous efficiency. P. J. Parbrook from Tyndall National Institute, University College Cork reported that 30 Â 30 μm 2 LEDs with 8 nm-thick quantum well grown on semipolar (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) GaN templates have a modulation bandwidth of over 800 MHz and data transmission rate of 1.5 Gb s À1 under nonreturn-to-zero on-off keying modulation scheme at 385 A cm À2 . [12] Daniel Feezell from the University of New Mexico reported a nonpolar m-plane InGaN/GaN microscale LED with an electrical À3 dB modulation bandwidth of 1.5 GHz and a carrier differential lifetime (DLT) of 200 ps at 1 kA cm À2 .…”

Section: Semi/nonpolar Leds Epitaxial Growthmentioning

confidence: 99%

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Improving the Modulation Bandwidth of GaN‐Based Light‐Emitting Diodes for High‐Speed Visible Light Communication: Countermeasures and Challenges

Wan

Wang

Huang

et al. 2021

Advanced Photonics Research

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Visible light communication (VLC) has attracted widespread attention for wireless communications. The popularity of GaN-based light-emitting diodes (LEDs) has also laid a solid foundation for the application of VLC. As the light source of VLC, LED's modulation bandwidth directly determines the speed of communication. Herein, reviewing progress on modulation bandwidth improvement schemes of GaN LEDs transmitter is reviewed, covering aspects from epitaxial to devices. Epitaxial approaches include c-polar facet epitaxial optimization, non/semipolar facet epitaxial growth, and chip scheme such as micro-LEDs, nano-LEDs, resonant cavity-LEDs (RC-LEDs), plasmon, and metacavity LEDs. In terms of white LEDs, approaches to tackle the slow Stokes transfer and long carrier life for conventional phosphors including new color-conversion materials (CCMs) and new energy transfer routes are reviewed. This review promotes the development of GaN-based LEDs as the transmitter for high-speed VLC.

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“…In VLC, micro‐LED plays a critical role as a high‐speed light source because small chip size can suppress the influence of resistance‐capacitance (RC) delay. [ 10,26–30 ] However, traditional c ‐plane InGaN QW LEDs suffer from built‐in polarization electric field and their carrier recombination lifetime is limited by quantum‐confined Stark effect (QCSE). The typical 3 dB modulation bandwidth of c ‐plane InGaN QW micro‐LEDs can be improved to several hundreds of MHz under high injection current density beyond kA cm −2 or even 10 kA cm −2 as high‐density carriers can not only improve the recombination rate but also screen the polarization electric field.…”

Section: Introductionmentioning

confidence: 99%

Green InGaN Quantum Dots Breaking through Efficiency and Bandwidth Bottlenecks of Micro‐LEDs

Wang

Chen

et al. 2021

Laser & Photonics Reviews

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Micro‐LEDs are regarded as ideal light sources for next‐generation display and high‐speed visible‐light communication (VLC). However, the conventional micro‐LEDs based on InGaN quantum well (QW) active region suffer from a low efficiency under small injection (below 1 A cm−2) due to the size‐dependent effect and a limited 3 dB bandwidth (hundreds of MHz) due to quantum‐confined Stark effect. Here, InGaN quantum dots (QDs) are proposed as the active region of micro‐LEDs to address these challenges for their strong localization and low‐strain features. Green InGaN QDs are self‐assembled under Stranski–Krastanov (SK) and Volmer–Weber (VW) modes by using metal organic vapor phase epitaxy. The SK QDs can shift the peak efficiency of a micro‐LED to an extremely low current density of 0.5 A cm−2 (almost two orders of magnitude lower compared to QW ones) with an external quantum efficiency of 18.2% (nearly two times higher than present green micro‐LEDs). Besides, green micro‐LEDs based on VW QDs reach a 3 dB bandwidth of 1.3 GHz. These results indicate that InGaN QDs can provide an ultimate solution to micro‐LEDs for display and VLC applications, especially since they are fully compatible with current light‐emitting diode (LED) industrial technology.

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Size-Dependent Bandwidth of Semipolar ( $11\overline {2}2$ ) Light-Emitting-Diodes

Cited by 37 publications

References 18 publications

Micro‐Light Emitting Diode: From Chips to Applications

Micro‐Light Emitting Diode: From Chips to Applications

Improving the Modulation Bandwidth of GaN‐Based Light‐Emitting Diodes for High‐Speed Visible Light Communication: Countermeasures and Challenges

Green InGaN Quantum Dots Breaking through Efficiency and Bandwidth Bottlenecks of Micro‐LEDs

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