Comparison of Beyond 1 GHz <i>C</i>-Plane Freestanding and Sapphire-Substrate GaN-Based micro-LEDs for High-Speed Visible Light Communication

Shan, Xinyi; Wang, Guobin; Zhu, Shijie; Qiu, Pengjiang; Lin, Runze; Wang, Zhou; Yuan, Zexing; Yan, Qiang; Cui, Xugao; Wang, Jianfeng; Bi, Wengang; Liu, Ran; Xu, Ke; Tian, Pengfei

doi:10.1109/jlt.2022.3224612

Cited by 13 publications

(4 citation statements)

References 35 publications

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“…The negligible extent of this shift can be credited to the efficient heat dissipation properties of the gallium nitride substrate. Furthermore, there is no evidence of a blueshift due to the quantum confined Stark effect (QCSE) as the current density increases, which can be largely ascribed to the superior crystal structure of the GaN-on-GaN [8]. The internal stress-induced polarization effects, common in materials, are also effectively mitigated in this structure.…”

Section: Resultsmentioning

confidence: 99%

P‐11.6: Minimal efficiency degradation and elevated radiometric power density of Ultraviolet‐A micro‐LED with homoepitaxial structure

Liu,

Wang,

Feng

et al. 2024

Symp Digest of Tech Papers

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As display technology continues to advance, UVA micro‐LEDs are becoming increasingly important in a variety of display and beyond‐display applications. In this study, we investigate the optoelectronic characteristics of UVA micro‐LEDs based on a homogeneously epitaxial structure on freestanding gallium nitride (GaN) substrates. The device exhibits a central wavelength of 390 nm, positioned at the overlap of UVA and visible light spectra. It demonstrates an impressively low ideality factor of 1.49 at 2.86 V and a series resistance of 9.88 Ω beyond 3 V. Optically, our device shows virtually no wavelength shift across a wide current density range of 0.1‐1000 A/cm2 , indicating exceptional optical stability and color accuracy. The emitted light is typical purple, reaching an expansive color gamut of 115.3% of Rec. 2020. Furthermore, the GaN‐on‐GaN structure, with its superior crystal structure and heat dissipation properties, results in a very low droop ratio in EQE. This ensures sustained high‐ power output at high current densities, showcasing great potential in applications such as 3D printing, maskless photolithography, and fluorescence tagging.

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Section: Resultsmentioning

confidence: 99%

P‐11.6: Minimal efficiency degradation and elevated radiometric power density of Ultraviolet‐A micro‐LED with homoepitaxial structure

Liu,

Wang,

Feng

et al. 2024

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“…Notably, GaN-based MicroLEDs often adopt sapphire substrates due to their excellent stability, light transparency, and well-established production techniques [6]. However, inherent challenges accompany this choice, including significant lattice and thermal stress mismatch between the GaN epitaxial layer and sapphire substrate, resulting in the generation of numerous defects and the manifestation of the Quantum Confined Stark Effect (QCSE) [7]. Furthermore, sapphire's suboptimal thermal conductivity, approximately 25W/(m•K) at 100°C, poses a hurdle as it leads to considerable heat dissipation during LED operation, thereby impacting luminous efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…GaN's compatibility with the epitaxial layer minimizes lattice and thermal stress, reducing defect generation. Additionally, GaN substrates exhibit superior thermal conductivity, addressing the heat dissipation concerns encountered with sapphire substrates [7]. This shift towards GaN substrates underscores a strategic move in the pursuit of overcoming limitations and optimizing the overall performance and efficiency of MicroLED devices.…”

Section: Introductionmentioning

confidence: 99%

P‐11.9: Enhanced Thermal Stability and High Color Accuracy in GaN‐on‐GaN Homoepitaxy Micro‐LEDs

Li,

Liu,

Feng

et al. 2024

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In the dynamic landscape of display technologies, the advent of MicroLEDs has sparked a revolutionary shift, promising unparalleled advancements in visual display capabilities. This study immerses itself in the realm of GaN‐based MicroLED devices, specifically delving into the nuanced effects of varying current density and temperature on the spectra of MicroLEDs with gallium nitride substrates. Through a meticulous comparative analysis, we unravel the optical distinctions between MicroLEDs utilizing gallium nitride and sapphire substrates. Additionally, our exploration extends to the examination of the diverse luminous intensity decay rates experienced by these devices under different substrate temperatures. The findings illuminate the pronounced optical advantages bestowed by gallium nitride substrates in GaNbased MicroLEDs, providing pivotal insights for the ongoing refinement and enhancement of these cutting‐edge display technologies.

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“…Lin et al reported a 10 µm c-plane green micro-LED achieving a record modulation bandwidth of 1.31 GHz at a current density of 41.4 kA/cm 2 and can achieve a maximum data rate of 5.789 Gbps in series combination after combined with an orthogonal frequency division multiplexing modulation scheme [ 29 ]. In another context, Shan et al made the first demonstration of a 20 m blue micro-LED that is constructed on a 2-inch freestanding c-plane GaN substrate and has a high bandwidth of over 1 GHz [ 30 ]. GaN-on-Si green micro-LEDs with high bandwidth of up to 613 MHz and a data rate of 4.65 Gbps were recently reported by Zhu et al in a nondestructive transfer printing technique and performance characterization [ 31 ].…”

Section: Introductionmentioning

confidence: 99%

Recent Advances in Micro-LEDs Having Yellow–Green to Red Emission Wavelengths for Visible Light Communications

et al. 2023

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Visible light communication (VLC), which will primarily support high-speed internet connectivity in the contemporary world, has progressively come to be recognized as a significant alternative and reinforcement in the wireless communication area. VLC has become more popular recently because of its many advantages over conventional radio frequencies, including a higher transmission rate, high bandwidth, low power consumption, fewer health risks, and reduced interference. Due to its high-bandwidth characteristics and potential to be used for both illumination and communications, micro-light-emitting diodes (micro-LEDs) have drawn a lot of attention for their use in VLC applications. In this review, a detailed overview of micro-LEDs that have long emission wavelengths for VLC is presented, along with their related challenges and future prospects. The VLC performance of micro-LEDs is influenced by a number of factors, including the quantum-confined Stark effect (QCSE), size-dependent effect, and droop effect, which are discussed in the following sections. When these elements are combined, it has a major impact on the performance of micro-LEDs in terms of their modulation bandwidth, wavelength shift, full-width at half maximum (FWHM), light output power, and efficiency. The possible challenges faced in the use of micro-LEDs were analyzed through a simulation conducted using Crosslight Apsys software and the results were compared with the previous reported results. We also provide a brief overview of the phenomena, underlying theories, and potential possible solutions to these issues. Furthermore, we provide a brief discussion regarding micro-LEDs that have emission wavelengths ranging from yellow–green to red colors. We highlight the notable bandwidth enhancement for this paradigm and anticipate some exciting new research directions. Overall, this review paper provides a brief overview of the performance of VLC-based systems based on micro-LEDs and some of their possible applications.

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Comparison of Beyond 1 GHz C-Plane Freestanding and Sapphire-Substrate GaN-Based micro-LEDs for High-Speed Visible Light Communication

Cited by 13 publications

References 35 publications

P‐11.6: Minimal efficiency degradation and elevated radiometric power density of Ultraviolet‐A micro‐LED with homoepitaxial structure

P‐11.6: Minimal efficiency degradation and elevated radiometric power density of Ultraviolet‐A micro‐LED with homoepitaxial structure

P‐11.9: Enhanced Thermal Stability and High Color Accuracy in GaN‐on‐GaN Homoepitaxy Micro‐LEDs

Recent Advances in Micro-LEDs Having Yellow–Green to Red Emission Wavelengths for Visible Light Communications

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