We present a grating model of two-dimensional (2D) rigorous coupled wave analysis (RCWA) to study top diffraction gratings on light-emitting diodes (LEDs). We compare the integrated-transmission of the non-grating, rectangular-grating, and triangular-grating cases for the same grating period of 6 µm, and show that the triangular grating has the best performance. For the triangular grating with 6-\mm period, the LED achieves the highest light transmission at 6-m grating bottom width and 2.9-µm grating depth. Compared with the non-grating case, the optimized light transmission improvement is about 74.6%. The simulation agrees with the experimental data of the thin polymer grating encapsulated flip-chip (FC) GaN-based LEDs for the light extraction improvement.
© 2008 Chinese Optics Letters
Xiaomin Jin, Bei Zhang, Tao Dai, Wei Wei, Xiangning Kang, Guoyi Zhang, Simeon Trieu, and Fei Wang, "Optimization of top polymer gratings to improve GaN LEDs light transmission," Chin. Opt. Lett. 6, 788-790 (2008)