| Summary: | 碩士 === 國立中興大學 === 精密工程學系所 === 102 === In this study, various chip sizes of vertical-type GaN light-emitting diodes (LEDs) with embedded electrodes were designed to improve current-spreading by using high reflection mirror, double-side roughness, laser lift-off and wafer bonding technology. Using SpeCLED simulation software simulates analysis of the current spreading effect, thermal analyses and light distribution on the chip performance of different chip sizes. There are three kinds of different chip sizes of vertical-type GaN LEDs with embedded electrodes: 14 ? 38 mil (S-LED)、20 ? 38 mil (M-LED) and 38 ? 38 mil (L-LED), respectively.
The light output power, wall-plug efficiency, and surface temperature of the vertical-type GaN LEDs with different chip sizes were compared. Under a current density of 700 mA/mm2 operation, the light output powers of the S-LED, M-LED and L-LED were 555, 485 and 432 mW, respectively. The 14.4 and 28.5% enhancement in the light output powers were achieved for the S-LED when compared with M-LED and L-LED700 mA/mm2. At a 700 mA/mm2, the values of wall-plug efficiency were estimated to be 19.2, 16.1 and 13.6% for the S-LED, M-LED and L-LED, corresponding to an enhancement of 19.3% and 41.2% in wall-plug efficiency of the S-LED in comparison to the M-LED and L-LED, respectively. It reveals that the S-LED has a significant improvement in the light extraction and current spreading. For the S-LED, M-LED and L-LED, the surface temperatures were measured to be 48.47, 58.25 and 73.53 °C, respectively. This indicates that the S-LED have a lower surface temperature and uniform temperature distribution. These results suggest that the S-LED exhibit high optoelectronic performance and uniform current spreading at operating high injection current (@700 mA/mm2), which has high potential for the applications.
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