Simulations of light extraction and light propagation properties of light emitting diodes featuring silicon carbide substrates

Lee, Yang–Chun; Lu, Tai-Yen; Lai, Yi‐Chyi; Chen, Hsuen‐Li; Ma, Dai-Liang; Lee, Cheng-Chung; Cheng, Shao-Chia

doi:10.1016/j.optmat.2013.01.027

Cited by 11 publications

(6 citation statements)

References 17 publications

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“…Since it has been proved that the spontaneous emission in LEDs could be classically represented by a point dipole source, 24) a point dipole polarized in the in-plane direction with wavelength of 450 nm has been chosen in simulations as those used in previous researches. 10,25) Both E ∥ x and E ∥ y polarized emission have been calculated, and then the average results were used for accuracy. The refractive index of GaN at 450 nm was taken to be 2.5 while that of SiC was set as 2.7, respectively.…”

Section: Model Of Simulation and Numerical Methodsmentioning

confidence: 99%

“…8,9) However, the light extraction performance of SiC substrate-based flip-chip vertical LEDs has been few discussed. 10,11) Previously, many attempts have been made to enhance the LEE of sapphire-based LEDs such as surface roughing, 12) PhCs, 13,14) nano-array surface, 15) and anti-reflection coatings. 16) However, the SiC substrate is friable, hard, chemi-cally inert, and very difficult to etch.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the light-extraction efficiency of SiC substrate-based flip-chip vertical light-emitting diodes with embedded photonic crystals

Kong

et al. 2016

Jpn. J. Appl. Phys.

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To improve the light-extraction efficiency (LEE) of flip-chip vertical light-emitting diodes (LEDs) grown on silicon carbide (SiC) substrate, embedded photonic crystals (PhCs) were alternatively introduced into the n-GaN layer of LEDs, since etching of the SiC substrate was very difficult. The finite-difference time-domain (FDTD) method was employed to investigate the combination effects of the micro-cavity and the embedded PhCs. The influences of the PhCs configurations on the LEE of LEDs were also examined to get an optimal structure. With the optimized parameters, about 20% enhancement of LEE was achieved comparing to planar SiC substrate-based flip-chip vertical LEDs. The LEE of conventional surface PhCs LEDs and double layer PhCs LEDs were also investigated for comparison. The results indicated that LEDs with carefully designed embedded PhCs could provide more LEE than surface PhCs LEDs. The structures proposed here offered scopes for the design of high-efficiency, high-power LEDs.

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Section: Model Of Simulation and Numerical Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of the light-extraction efficiency of SiC substrate-based flip-chip vertical light-emitting diodes with embedded photonic crystals

Kong

et al. 2016

Jpn. J. Appl. Phys.

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“…Overheating of LEDs can be avoided by using SiC due to its extremely low thermal expansion and high thermal conductivity. The light emission and extraction from SiC-based LEDs have not been discussed in detail in the literature since it is extremely challenging to understand its optoelectronics attributes [20,21]. The focus of recent research has been to improve the performance of the LEDs with different fabrication techniques [22,23].…”

Section: Introductionmentioning

confidence: 99%

Modeling and Simulations of 4H-SiC/6H-SiC/4H-SiC Single Quantum-Well Light Emitting Diode Using Diffusion Bonding Technique

et al. 2021

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In the last decade, silicon carbide (SiC) has emerged as a potential material for high-frequency electronics and optoelectronics applications that may require elevated temperature processing. SiC exists in more than 200 different crystallographic forms, referred to as polytypes. Based on their remarkable physical and electrical characteristics, such as better thermal and electrical conductivities, 3C-SiC, 4H-SiC, and 6H-SiC are considered as the most distinguished polytypes of SiC. In this article, physical device simulation of a light-emitting diode (LED) based on the unique structural configuration of 4H-SiC and 6H-SiC layers has been performed which corresponds to a novel material joining technique, called diffusion welding/bonding. The proposed single quantum well (SQW) edge-emitting SiC-based LED has been simulated using a commercially available semiconductor device simulator, SILVACO TCAD. Moreover, by varying different design parameters, the current-voltage characteristics, luminous power, and power spectral density have been calculated. Our proposed LED device exhibited promising results in terms of luminous power efficiency and external quantum efficiency (EQE). The device numerically achieved a luminous efficiency of 25% and EQE of 16.43%, which is at par performance for a SQW LED. The resultant LED structure can be customized by choosing appropriate materials of varying bandgaps to extract the light emission spectrum in the desired wavelength range. It is anticipated that the physical fabrication of our proposed LED by direct bonding of SiC-SiC wafers will pave the way for the future development of efficient and cost-effective SiC-based LEDs.

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“…In this paper, ZnO nanoparticle porous layers with a high refractive index were fabricated on the surface of the SiC substrate of a GaN-based LED, which was multiple-beveled with microscale textures, and used to enhance the light extraction efficiency. The LED was fabricated with the flip-chip technique, which is an effective way to enhance heat dissipation and the output of a high-power LED [17]. We demonstrated that a further significant enhancement of the light extraction efficiency of flip-chip light-emitting diodes (FC-LEDs) can be realized with the porous nanoparticle coatings, even if the surface was beveled already with microscale textures.…”

Section: Introductionmentioning

confidence: 99%

Dual enhancement of light extraction efficiency of flip-chip light-emitting diodes with multiple beveled SiC surface and porous ZnO nanoparticle layer coating

Mao

Chen

et al. 2015

Nanotechnology

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A porous ZnO nanoparticle layer coating composed of columnar ZnO nanoparticle piles and a multiple-beveled substrate was used to enhance the light extraction efficiency of GaN-based flip-chip light-emitting diodes (FC-LEDs), which were grown on high-purity SiC substrates. The SiC substrate was multiple-beveled by fabricating an 'X' pattern on the face of it, followed by a deposition of a porous ZnO nanoparticle layer on the 'X'-patterned surface. A porous ZnO nanoparticle layer was fabricated with gas phase cluster beam deposition in a glancing incidence. The incident angular-resolved light transmission of the ZnO nanostructure beyond the critical angle of total internal reflection (TIR) was greatly enhanced. The light output power of the LED was improved by nearly 60% compared to the original planar GaN-based LED on an SiC substrate (FC-SLED), which contained a significant enhancement supplemental to the 18% electroluminescence (EL) enhancement realized with the 'X'-pattern beveling. We demonstrated that a dual enhancement of light extraction efficiency was achieved by using the hierarchical surface consisting of microscale textures (the multiple-beveled surfaces) and nanoscale structures (the ZnO nanoparticle layers).

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Simulations of light extraction and light propagation properties of light emitting diodes featuring silicon carbide substrates

Cited by 11 publications

References 17 publications

Analysis of the light-extraction efficiency of SiC substrate-based flip-chip vertical light-emitting diodes with embedded photonic crystals

Analysis of the light-extraction efficiency of SiC substrate-based flip-chip vertical light-emitting diodes with embedded photonic crystals

Modeling and Simulations of 4H-SiC/6H-SiC/4H-SiC Single Quantum-Well Light Emitting Diode Using Diffusion Bonding Technique

Dual enhancement of light extraction efficiency of flip-chip light-emitting diodes with multiple beveled SiC surface and porous ZnO nanoparticle layer coating

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