Parameters optimization of nanopatterned sapphire substrates for enhancing light extraction efficiency of GaN-based LEDs

Zhang, Pengcheng; Wen, Qiuling; Xu, Xipeng

doi:10.1016/j.optcom.2020.125548

Cited by 9 publications

(3 citation statements)

References 29 publications

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“…3 However, the LEE remains extremely low due to the effects of total internal reflection (TIR) and Fresnel reflection. 4 Numerous light extraction techniques have been proposed and researched to address the aforementioned issues, such as surface roughing, 5 flip-chip, 6 photonic crystals (PhCs), 7,8 nanoarray surfaces, 9,10 nano-patterned sapphire substrates, 11 and others. In particular, the application of PhCs has received a lot of attention during the last decade as a light extractor to enhance the LEE through regulating the direction of light emissions.…”

Section: Introductionmentioning

confidence: 99%

Enhancing light extraction efficiency of GaN-based light-emitting diodes with reticulated photonic crystals

Zheng

Gong

et al. 2023

J. Nanophoton.

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We have proposed reticulated photonic crystals (PhCs) on the top surface of conventional light-emitting diodes (LEDs) to increase the light extraction efficiency (LEE). The rigorous electromagnetic simulations based on the three-dimensional finite-difference time-domain method were carried out to investigate the optical properties of reticulated PhCs LEDs and mechanisms of reticulated PhCs improving the LEE of LEDs. Results from these simulations showed that more than 115% enhancement of LEE had been achieved for LEDs with reticulated PhCs period of 200 nm and depth of 200 nm. This study provides an innovative approach to the creation of high-efficiency LEDs of the upcoming generation.

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Section: Introductionmentioning

confidence: 99%

Enhancing light extraction efficiency of GaN-based light-emitting diodes with reticulated photonic crystals

Zheng

Gong

et al. 2023

J. Nanophoton.

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“…The PSS can get more photons generated in the active layer into the air to enhance the LEE. [7,8] To date, different types and morphologies of PSS, from micropatterns to nanopatterns, such as cone-shaped PSS, [9] pyramidally PSS, [10,11] volcano-shaped PSS, [12,13] micro-hole patterns, [14] concave-hexagonal PSS, [15] lensshaped PSS, [16] have been employed in use of GaN-based LEDs. The micro-patterned sapphire substrates (MPSSs) show great performance in both enhancing the LEE and reducing the TD.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a hierarchical patterned sapphire substrate for GaN-based light-emitting diodes

Zha

et al. 2023

International Conference on Optical Technology, Semiconductor Materials, and Devices (OTSMD 2022)

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Microscale or nanoscale patterns with specific structures on sapphire substrate can effectively reduce the dislocation defects of gallium nitride (GaN) material and improve the quality of gallium nitride crystal during the epitaxy growth of GaN-based light-emitting diodes, thus improving the internal quantum efficiency of LED luminescence. Numbers of methods have been used to fabricated patterned sapphire substrate. But most methods remain on the micron scale. In this work, the nickel annealing technique was introduced to fabricate a novel sapphire substrate, hierarchical patterned sapphire substrate (HPSS), which has typical characteristics of nano sapphire pillars on a micro-patterned sapphire substrate (MPSS) used for GaN-based light-emitting diodes (LEDs). Nano-pillars with an average feature size of about 110 nm and feature surface density of >2.339×10 9 cm -2 were obtained on commercial MPSS through this method. This nickel annealing technique provides an extremely simple, cost-effective and universal method to fabricate hierarchical patterns with 2-inch wafer-scale. What's more, the substrates can be not only sapphire but also extended to silicon, quartz and other heat-resisting materials which are widely used in photoelectric devices and micro/nanofabrication, making it a promising method to fabricate patterned substrate for industrial applications.

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“…For maximum extraction efficiency, there must be a strong coupling between the trapped waveguide modes and PhC structure. The optimization parameters of PhC are related to the vertical structure of the LED [6,7,14], and parameters of PhCs. Firstly, the etch depth plays very important role in cross-coupling of trapped modes with the leaky Bloch modes associated with the PhC [6,8].…”

Section: Introductionmentioning

confidence: 99%

Complex Analysis of Emission Properties of LEDs with 1D and 2D PhC Patterned by EBL

et al. 2020

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In this paper, we present the optical and electrical properties of surface-patterned GaAs-based Multiquantum Well (MQW) light emitting diodes (LEDs) with one- and two-dimensional photonic crystal (PhC) structures. Optical properties were analyzed in the near and far field, measured by a near-field scanning optical microscope and with a goniophotometer. We demonstrated a strong effect of patterned PhC on the radiation properties and the light extraction efficiency. Enormous surface emission enhancement reaching 110% confirmed the strong effect of the patterned structure on the coupling of the guided modes into the surface emission. Additionally, the considerable effect of the PhC structure diffraction on radiation pattern was confirmed in the near and far field and is in good agreement with the simulated shape of the optical field.

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Parameters optimization of nanopatterned sapphire substrates for enhancing light extraction efficiency of GaN-based LEDs

Cited by 9 publications

References 29 publications

Enhancing light extraction efficiency of GaN-based light-emitting diodes with reticulated photonic crystals

Enhancing light extraction efficiency of GaN-based light-emitting diodes with reticulated photonic crystals

Fabrication of a hierarchical patterned sapphire substrate for GaN-based light-emitting diodes

Complex Analysis of Emission Properties of LEDs with 1D and 2D PhC Patterned by EBL

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