Numerical simulation for light extraction in nano-patterned light-emitting diodes.

We present numerical simulation results using the three-dimensional finite-difference time-domain method for light extraction in light-emitting diodes (LEDs) constructed on nano-patterned n-GaN substrates. We studied reasonable conditions for numerical calculation, including excitation source conditions, simulation size conditions, and boundary conditions and examined the effects of the size and distribution of nano-patterns on light extraction. Our findings revealed optimized structures for high extraction efficiency. Our simulation results were consistent with our experimental results and show the potential for the design of LED structures optimized for high light extraction.