Use of anisotropic laser etching to the top n-GaN layer to alleviate current-crowding effect in vertical-structured GaN-based light-emitting diodes

2007 ◽  
Vol 90 (4) ◽  
pp. 041115 ◽  
Author(s):  
Tron-Min Chen ◽  
Shui-Jinn Wang ◽  
Kai-Ming Uang ◽  
Shiue-Lung Chen ◽  
Wei-Chih Tsai ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Current Crowding ◽  
Crowding Effect ◽  
Laser Etching ◽  
Light Emitting

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.

A Study of Current Crowding and Its Effects on the Carrier Spill-over in InGaN/GaN Blue Light-emitting Diodes

2014 ◽  
Vol 64 (11) ◽  
pp. 1054-1058
Author(s):  
Hye-Jung YU ◽  
Jin-Gyu LEE ◽  
Tae-Soo KIM ◽  
Nan-Cho OH ◽  
Jung-Hoon SONG*
Keyword(s):  
Blue Light ◽  
Light Emitting Diodes ◽  
Current Crowding ◽  
Light Emitting

scholarly journals InGaN-based vertical light-emitting diodes with acid-modified graphene transparent conductor and highly reflective membrane current blocking layer

2013 ◽  
Vol 469 (2151) ◽  
pp. 20120652 ◽  
Author(s):  
Liancheng Wang ◽  
Yiyun Zhang ◽  
Xiao Li ◽  
Zhiqiang Liu ◽  
Lian Zhang ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Optical Power ◽  
Blocking Layer ◽  
Current Crowding ◽  
Transparent Conductor ◽  
Acid Modification ◽  
Spreading Effect ◽  
Light Emitting ◽  
Current Blocking Layer ◽  
Current Blocking

Vertical light-emitting diodes (VLEDs) with a highly reflective membrane (HRM) as current blocking layer (CBL) and a graphene transparent conductive layer (TCL) have been fabricated and characterized. High reflectance of HRM and high transmittance of graphene ensure less loss of the optical power. The VLEDs show improved optical output and less efficiency droop, thanks to the current spreading effect of HRM CBL and graphene TCL by preventing current crowding under the top electrode and thus increasing the internal and external quantum efficiency. With further acid modification, forward electrical characteristics of VLEDs are improved.

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