Improvement of light extraction from micro-pattern encapsulated GaN-based LED by imprinting

Kui Bao; Bei Zhang; XiangNing Kang; Tao Dai; Chang Xiong; GuoYi Zhang; Yong Chen

doi:10.1117/12.763285

13 February 2008 Improvement of light extraction from micro-pattern encapsulated GaN-based LED by imprinting

Kui Bao, Bei Zhang, XiangNing Kang, Tao Dai, Chang Xiong, GuoYi Zhang, Yong Chen

Proceedings Volume 6910, Light-Emitting Diodes: Research, Manufacturing, and Applications XII; 69100N (2008) https://doi.org/10.1117/12.763285
Event: Integrated Optoelectronic Devices 2008, 2008, San Jose, California, United States

Abstract

We have demonstrated an improvement of light extraction from GaN based flip-chip LEDs by patterning encapsulant. Two dimensional (2D) micron-scale patterns of encapsulant were realized by using imprint technique of thermosetting polymer. This approach has several advantages such as technical simplification, low cost and freedom of material choice. In this work, we fabricated 2D micron-scale patterns with the triangular or sinusoidal profiles on the polymer encapsulated GaN-based flip-chip LEDs. The enhancement factors of light extraction of GaN LEDs with the patterned encapsulant comparing to the flat encapsulated LEDs are about 32% and 47% corresponding to the triangular and sinusoidal profiles, respectively. To evaluate the concept of a diffraction grating in enhancement of light extraction, we performed a simulation of diffraction based on simplified one-dimensional (1D) rigorous coupled wave analysis (RCWA). The calculation reveals that the grating of sinusoidal profile has greater transmittance than that of triangular profile which is in the same trend with the experimental results. These results provide a guideline for improvement of the LED light extraction.

Citation Download Citation

Kui Bao, Bei Zhang, XiangNing Kang, Tao Dai, Chang Xiong, GuoYi Zhang, and Yong Chen "Improvement of light extraction from micro-pattern encapsulated GaN-based LED by imprinting", Proc. SPIE 6910, Light-Emitting Diodes: Research, Manufacturing, and Applications XII, 69100N (13 February 2008); https://doi.org/10.1117/12.763285

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