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Light Extraction Improvement of GaN LEDs using Nano-scale Top Transmission Gratings
Eleventh International Conference on Solid State Lighting: San Diego, CA
  • Greg Chavoor, California Polytechnic State University - San Luis Obispo
  • Xiaomin Jin, California Polytechnic State University - San Luis Obispo
  • Ashton Ellaboudy, California Polytechnic State University - San Luis Obispo
  • Xing-Xing Fu, Peking University
  • Xiang-Ning Kang, Peking University
  • Bei Zhang, Peking University
  • Guo-Yi Zhang, Peking University
Publication Date
8-22-2011
Abstract
In this paper, we use a Finite-Difference Time-Domain GaN LED model to study constant wave (CW) average power of extracted light. The structure simulated comprises of a 200nm-thick p-GaN substrate, 50nm-thick MQW, 400nm-thick n-GaN substrate, and a 200nm n-GaN two-dimensional Photonic Crystal(2PhC) grating. We focus on optimizing three design parameters: grating period (A), grating height (d), and fill factor (FF). In the primary set of simulations, we fix the fill factor at 50% and simulate ten different grating periods (100 to 1000nm in steps of 100nm) and four different grating heights (50 to 200nm in steps of 50nm), and calculate the average power output of the device. The results from these simulations show that for both conical and cylindrical gratings, the maxmium light extraction improvement occurs when A =100nm. In the second set of simulations, we maintain a constant grating period A = 100nm and sweep the fill factor from 25 to 75%. The results of these simulations show that the fill factor affects clyindrical and conical gratings differently. As a whole, we see that the nano-structure grating mostly depends on period, but also depends on height and fill factor. The grating structure improves light extraction in some cases, but not all.
Number of Pages
9
Publisher statement
One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
Citation Information
Greg Chavoor, Xiaomin Jin, Ashton Ellaboudy, Xing-Xing Fu, et al.. "Light Extraction Improvement of GaN LEDs using Nano-scale Top Transmission Gratings" Eleventh International Conference on Solid State Lighting: San Diego, CA (2011)
Available at: http://works.bepress.com/xjin/36/