The Light Extraction Efficiency of GaN-based LED with Air-Hole Photonic Crystal Structures

NANO ◽  
2021 ◽  
Vol 16 (09) ◽  
Author(s):  
Daohan Ge ◽  
Zhou Hu ◽  
Kai Gao ◽  
Liqiang Zhang
Keyword(s):  
Photonic Crystal ◽  
Extraction Efficiency ◽  
Structural Parameters ◽  
Fdtd Method ◽  
Structure Design ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Hole Radius ◽  
Air Hole

In order to improve the light extraction efficiency (LEE) of GaN-based light-emitting diodes (LEDs), a layer of cylindrical air-hole photonic crystal (PC) structure inserted into P-GaN is proposed and investigated numerically. Finite difference time domain (FDTD) method is used to make a series of simulations in the LEE of GaN-based LED with air-hole photonic crystal structure. According to the variable-controlling approach, the PC structure is simulated and optimized. The results of the simulations show that the LEE depends on the PC’s position and relevant structural parameters. When PC is etched in the active layer, and its dielectric constant [Formula: see text][Formula: see text][Formula: see text]m, etching [Formula: see text][Formula: see text][Formula: see text]m and air-hole radius [Formula: see text][Formula: see text][Formula: see text]m, higher LEE is obtained as 44.5%, translated into a 13.6-fold enhancement for the case of a planar LED. The remarkable enhancement is of particular interest for improving LEE of LED and provides a theoretical reference for future LED structure design efforts.

scholarly journals Study on Modulation Bandwidth and Light Extraction Efficiency of Flip-Chip Light-Emitting Diode with Photonic Crystals

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 767 ◽  
Author(s):  
Hong Wang ◽  
Ming Zhong ◽  
Lijun Tan ◽  
Wei Shi ◽  
Quanbin Zhou
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Flip Chip ◽  
Extraction Efficiency ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Experimental Result ◽  
Modulation Bandwidth ◽  
Light Emitting ◽  
Current Densities

In this study, the photonic crystal structure is employed to increase both the light extraction efficiency and the modulation bandwidth of flip-chip GaN-based light-emitting diodes (LEDs). The finite difference time domain method is utilized to investigate the influence of structure of photonic crystals on the Purcell factor and light extraction efficiency of flip-chip GaN-based LEDs. Simulation results show that the modulation bandwidth is estimated to be 202 MHz at current densities of 1000 A/cm2. The experimental result of modulation bandwidth is in accord with the simulation. The optical f-3dB of the device achieves 212 MHz at current densities of 1000 A/cm2 and up to 285 MHz at current densities of 2000 A/cm2. This design of photonic crystal flip-chip LED has the potential for applications in high-frequency visible light communication.

High extraction efficiency in GaN-based light-emitting diodes with air-hole photonic crystal slab

2014 ◽  
Vol 28 (21) ◽  
pp. 1450173 ◽  
Author(s):  
Dan Liu ◽  
Hui Liu ◽  
Jin Hou ◽  
Yihua Gao
Keyword(s):  
Photonic Crystal ◽  
Light Emitting Diodes ◽  
Extraction Efficiency ◽  
Three Dimensional ◽  
Expansion Method ◽  
Light Emitting ◽  
Hole Radius ◽  
Parameters Tuning ◽  
Gan Led ◽  
Air Hole

In this paper, extraction efficiency in simplified and layered light-emitting diodes (LEDs) of GaN photonic crystal with periodic air holes is studied by three-dimensional finite-difference time-domain method. Photonic band structures of the photonic crystal are obtained by plane-wave expansion method. The results about simplified GaN -LED show that extraction efficiency is very sensitive to the structure parameters tuning, and increases considerably inside the transverse-electric-like gap region. A maximum extraction efficiency above 90% can be achieved. The effects of the PC thickness and air-hole radius on relative extraction efficiency of layered GaN -LED are analyzed. They show optimal values to obtain high relative extraction efficiency.

scholarly journals The Effect of Anisotropy on Light Extraction of Organic Light-Emitting Diodes with Photonic Crystal Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Wei Xu ◽  
Yang Li
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Light Emitting Diodes ◽  
Extraction Efficiency ◽  
Organic Light Emitting Diodes ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Organic Light ◽  
Triangle Lattice

The light extraction efficiency of organic light-emitting diodes (OLED) is greatly limited due to the difference in refractive indexes between materials of OLED. We fabricated OLED with photonic crystal microstructures in the interface between the glass substrate and the ITO anode. The light extraction efficiency can be improved by utilizing photonic crystals; however, the anisotropy effect of light extraction was clearly observed in experiment. To optimize the device performance, the effect of photonic crystal on both light extraction and angular distribution was investigated using finite-difference time domain (FDTD) method. We simulated the photonic crystals with the structure of square lattice and triangle lattice. We analyzed the improvement of these structures in the light extraction efficiency of the OLED and the influence of arrangement, depth, period, and diameter on anisotropy. The optimized geometric parameters were provided, which will provide the theoretical support for designing the high performance OLED.

scholarly journals Lattice Constant Effect on Diffracted Transmission of ITO Periodic Nanostructures and Improvement of the Light Extraction Efficiency of Light-Emitting Diodes

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 693
Author(s):  
Zhanxu Chen ◽  
Runhong Ding ◽  
Feng Wu ◽  
Wei Wan
Keyword(s):  
Lattice Constant ◽  
Light Emitting Diodes ◽  
Extraction Efficiency ◽  
Fdtd Method ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Enhancement Effect ◽  
Periodic Nanostructures ◽  
Light Emitting ◽  
Lattice Constants

We studied the effects of the lattice pitch of indium-doped tin oxide (ITO) periodic nanostructures on the diffracted transmission to improve the light extraction efficiency of light-emitting diodes (LEDs). Periodic hexagonal ITO nanopillars with lattice constants of 600, 800, 1050, 1200, and 1600 nm were fabricated on ITO electrodes. We found that the light extraction efficiency strongly depended on the lattice constant. The LEDs with a lattice constant of 800 nm ITO nanopillars showed an increase in light extraction of 83%. In addition, their electrical properties were not degraded compared to conventional LEDs. The dependence of the extraction efficiency on the lattice constant was also calculated using a 3D finite-difference time-domain (FDTD) method, and this dependence was in good agreement with the experimental measurements. The transmission of each diffraction order and with the total transmission of ITO nanopillars with different lattice constants were calculated using the FDTD method to investigate the enhancement effect.

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