The use of LEDs has become commonplace for applications ranging from lighting, indicator lamps, and displays for mobile phones, tablet PCs, and TVs. LEDs offer high relative efficiency, lower energy consumption, high reliability, sharper colors, and smaller sizes, all important factors for these applications.
Numerical simulations are tedious since LEDs are inherently incoherent. Most traditional simulation techniques cannot easily manage incoherence since they are based on directly solving Maxwell's equations or some derived form such as the Wave equation. Moreover, the optical design for LEDs is further complicated due to factors like multiple interfaces, the use of novel materials and structures, dispersion, surface roughness, and the use of gratings to enhance efficiency, etc.
This application note describes the simulation of the 3D GaN-based LED structure shown in Fig. 1 and is based on Ref. 1. It has a hexagonal photonic crystal (PhC etched into the top).