Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure

A three-dimensional model with finite difference and time domain was established to investigate the enhancement of the light output intensity of GaN light-emitting diodes (LEDs) with bottom pillar (BP) structure. Through comparing the normalized light extraction intensity of GaN LEDs with or without BP in different dimensions, the theoretical results show that the light output intensity in the LED with BP structure involved could be enhanced by about 30%. The influence of BP structure on the light output intensity of a LED could be explained by the physical model of light interaction. In addition, the experimental results also show the same trend to the theoretical calculations.