Performance comparison of GaN-based LEDs with different electrode shapes

At present, the light output efficiency of LED is generally low, which is caused by many reasons such as the absorption of light by the lattice, the absorption of light by the substrate, and the reflection and total internal reflection during the light output process. In recent years, there have been many studies on improving the light output efficiency of LEDs, among which improving the shape of LED electrodes is a new branch [1-2]. There are three aspects to pay attention to when optimizing the electrode shape of LEDs: ① Use the method of using the n electrode to surround the p electrode, so that the current can enter the n electrode from the p electrode over the largest possible area, increasing the effective light-emitting length; ② The distance between the n and p electrodes should be equal to make the current as evenly distributed as possible; ③ The n electrode should be distributed on the outside, which is the same as the reason for ①. Improving the light output efficiency of LEDs will improve the electro-optical conversion efficiency of LEDs to a certain extent, which has an important impact on the energy-saving advantages of LEDs. However, JS Yun et al. [2] only made simple optimizations on commonly used electrodes. The previous work of this paper designed complex optimized electrodes and optimized the electrodes through software simulation results to improve the light output efficiency.

In order to experimentally verify the software simulation, this experiment trial-produced the blue light chips with 6 optimized electrodes simulated in the early stage, and made a detailed comparative analysis of the theoretical results and experimental results in optics, electricity and reliability. The test results were used to verify the advantages of the optimized electrodes in various aspects and to predict the lifespan of various electrodes.