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.

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.

Position dependence of extraction efficiency in organic light-emitting diodes with photonic crystal structure

2013 ◽  
Vol 11 (6) ◽  
pp. 062302-62305
Author(s):  
Saijun Huang Saijun Huang ◽  
Zhicheng Ye Zhicheng Ye ◽  
Jiangang Lu Jiangang Lu ◽  
Yikai Su Yikai Su ◽  
Chaoping Chen Chaoping Chen ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Photonic Crystal ◽  
Light Emitting Diodes ◽  
Extraction Efficiency ◽  
Organic Light Emitting Diodes ◽  
Photonic Crystal Structure ◽  
Light Emitting ◽  
Organic Light ◽  
Position Dependence

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.

Analytical Calculation of the Light Extraction Efficiency of Micro Cavities Light-Emitting Diodes

2007 ◽  
Vol 364-366 ◽  
pp. 98-103
Author(s):  
Paul C.P. Chao ◽  
Lun De Liao ◽  
Yi Hua Fan ◽  
Chien Yu Shen ◽  
Yung Yuan Kao ◽  
...  
Keyword(s):  
Extraction Efficiency ◽  
Substrate Surface ◽  
Surface Texturing ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Gan Led ◽  
Micro Cavity

Using TracePro® Monte-Carlo ray-tracing simulations, this paper investigates the improved light extraction efficiency (LEE) obtained by patterning the surface and/or substrate of GaN LEDs with unique three-dimensional micro-cavity patterns. The simulations commence by considering the case of a sapphire-based GaN LED. The effects on the LEE of the micro-cavity dimensions, the absorption coefficient of the active layer, the point source location, and the chip dimensions are systematically examined. Subsequently, the LEE performance of the sapphire-based GaN LED is compared with that of a thin-GaN LED for various surface texturing strategies. In general, the results show that patterning either the surface or the substrate of the LED structure provides an effective improvement in the LEE of both the sapphire-based GaN LED and the thin- GaN LED. For both LED structures, the maximum LEE enhancement is obtained by patterning both the upper surface of the LED and the substrate surface. However, the simulation results indicate that the improvement obtained in the LEE is the result primarily of pattering the upper surface of the LED.

scholarly journals Simulation of an Improved Design for n-Electrode with Holes for Thin-GaN Light-Emitting Diodes

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Farn-Shiun Hwu
Keyword(s):  
Light Emitting Diodes ◽  
Three Dimensional ◽  
Light Output ◽  
Electrical Characteristics ◽  
Light Emitting ◽  
Temperature Distributions ◽  
Gan Led ◽  
Wall Plug Efficiency ◽  
Improved Design ◽  
Novel Design

A novel design is proposed for n-electrode with holes to be applied in Thin-GaN light-emitting diodes (LEDs). The influence of the n-electrode with holes on the thermal and electrical characteristics of a Thin-GaN LED chip is investigated using a three-dimensional numerical simulation. The variations in current density and temperature distributions in the active layer of n-electrodes both with and without holes are very tiny. The percentages of light output from these holes are 29.8% and 38.5% for cases with 5 μm holes and 10 μm holes, respectively; the side length of the n-electrode (L) is 200 μm. Furthermore, the percentage increases with the size of the n-electrode. Thus, the light output can be increased 2.45 times using the n-electrode with holes design. The wall-plug efficiency (WPE) can also be improved from 2.3% to 5.7%. The most appropriate n-electrode and hole sizes are determined by WPE analysis.

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