Novel Electrode Design for Integrated Thin-Film GaN LED Package With Efficiency Improvement

Abstract

This letter proposes a novel electrode structure for thin-GaN LED applications. The structure enhances light extraction and wall-plug efficiency in thin-GaN LEDs. To enhance light extraction in thin-GaN LEDs and solve current crowding effects caused by electrodes composed of metal, conventional n-GaN electrodes were replaced with ITO conductive films because of their high optical transparency. Simulation results show that the thin-GaN LEDs that use ITO as the nonshielded electrode have a more uniform current density distribution on the n-GaN surface and a higher average internal quantum efficiency than conventional metal electrodes. Furthermore, when a current of 200 mA was applied, the thin-GaN LEDs using the proposed electrode had a 40% increase in light-output power and a significant decrease in chip temperature compared to the use of conventional electrodes. The results indicate that the nonshielded ITO electrode design enhances the light extraction efficiency and avoids the accumulation of heat because of its uniform current density distribution.Index Terms-LED, nonshielding electrode, thin-film package LED (TFP LED).

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