scholarly journals Effects of interfaces and current spreading on the thermal transport of micro-LEDs for kA-per-square-cm current injection levels

RSC Advances ◽  
2019 ◽  
Vol 9 (42) ◽  
pp. 24203-24211
Author(s):  
Chengcheng Li ◽  
Zhizhong Chen ◽  
Fei Jiao ◽  
Jinglin Zhan ◽  
Yifan Chen ◽  
...  
Keyword(s):  
Thermal Imaging ◽  
Light Emitting Diodes ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Forward Voltage ◽  
Infrared Thermal Imaging ◽  
Light Emitting ◽  
Sapphire Substrates ◽  
Thermal Transient ◽  
Transient Measurements

The three-dimensional thermal characteristics of micro-light-emitting diodes (μLEDs) on GaN and sapphire substrates were studied with forward-voltage methods, thermal transient measurements, and infrared thermal imaging.

Understanding the Role of Ion Migration in the Operation of Perovskite Light-Emitting Diodes by Transient Measurements

2020 ◽  
Vol 12 (43) ◽  
pp. 48845-48853
Author(s):  
Qi Dong ◽  
Juliana Mendes ◽  
Lei Lei ◽  
Dovletgeldi Seyitliyev ◽  
Liping Zhu ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Ion Migration ◽  
Light Emitting ◽  
Transient Measurements

scholarly journals Numerical Simulation on Electrical-Thermal Properties of Gallium-Nitride-Based Light-Emitting Diodes Embedded in Board

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Xing-ming Long ◽  
Rui-jin Liao ◽  
Jing Zhou
Keyword(s):  
Finite Element ◽  
Gallium Nitride ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Thermal Characteristics ◽  
Junction Temperature ◽  
Current Crowding ◽  
Total Thermal Resistance ◽  
Light Emitting ◽  
Packaging Structure

The electrical-thermal characteristics of gallium-nitride- (GaN-) based light-emitting diodes (LED), packaged by chips embedded in board (EIB) technology, were investigated using a multiphysics and multiscale finite element code, COMSOL. Three-dimensional (3D) finite element model for packaging structure has been developed and optimized with forward-voltage-based junction temperatures of a 9-chip EIB sample. The sensitivity analysis of the simulation model has been conducted to estimate the current and temperature distribution changes in EIB LED as the blue LED chip (substrate, indium tin oxide (ITO)), packaging structure (bonding wire and chip numbers), and system condition (injection current) changed. This method proved the reliability of simulated results in advance and useful material parameters. Furthermore, the method suggests that the parameter match on Shockley's equation parameters, Rs, nideal, and Is, is a potential method to reduce the current crowding effect for the EIB LED. Junction temperature decreases by approximately 3 K to 10 K can be achieved by substrate thinning, ITO, and wire bonding. The nonlinear-decreasing characteristics of total thermal resistance that decrease with an increase in chip numbers are likely to improve the thermal performance of EIB LED modules.

scholarly journals Suppressing the Initial Growth of Sidewall GaN by Modifying Micron-Sized Patterned Sapphire Substrate with H3PO4-Based Etchant

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 622 ◽  
Author(s):  
Wen-Yang Hsu ◽  
Yuan-Chi Lian ◽  
Pei-Yu Wu ◽  
Wei-Min Yong ◽  
Jinn-Kong Sheu ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
Light Emitting Diodes ◽  
Ex Situ ◽  
Initial Growth ◽  
Patterned Sapphire Substrate ◽  
Light Emitting ◽  
Sapphire Substrates ◽  
Patterned Sapphire Substrates

Micron-sized patterned sapphire substrates (PSS) are used to improve the performance of GaN-based light-emitting diodes (LEDs). However, the growth of GaN is initiated not only from the bottom c-plane but also from the sidewall of the micron-sized patterns. Therefore, the coalescence of these GaN crystals creates irregular voids. In this study, two kinds of nucleation layers (NL)—ex-situ AlN NL and in-situ GaN NL—were used, and the growth of sidewall GaN was successfully suppressed in both systems by modifying the micron-sized PSS surface.

scholarly journals Polarization of light emission by 460nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates

2007 ◽  
Vol 91 (5) ◽  
pp. 051117 ◽  
Author(s):  
Martin F. Schubert ◽  
Sameer Chhajed ◽  
Jong Kyu Kim ◽  
E. Fred Schubert ◽  
Jaehee Cho
Keyword(s):  
Light Emitting Diodes ◽  
Light Emission ◽  
Light Emitting ◽  
Sapphire Substrates ◽  
Polarization Of Light

scholarly journals Enhanced light extraction of nonpolar a-plane (11-20) GaN light emitting diodes on sapphire substrates by photo-enhanced chemical wet etching

2010 ◽  
Vol 18 (9) ◽  
pp. 9728 ◽  
Author(s):  
Younghun Jung ◽  
Jihyun Kim ◽  
Soohwan Jang ◽  
Kwang Hyeon Baik ◽  
Yong Gon Seo ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Wet Etching ◽  
Light Extraction ◽  
Light Emitting ◽  
Sapphire Substrates

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.

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