Enhancement of the light extraction efficiency of flip-chip light-emitting diodes fabricated on patterned silicon carbide and sapphire substrates

Total internal reflection (TIR) effect leads to low light extraction efficiency (LEE) of the GaN LEDs on SiC and sapphire substrates. The LEE enhancements of the GaN based flip-chip light-emitting diodes (FC-LEDs) on patterned substrates are investigated by experiments and simulations. The optical output power of the FC-LEDs on patterned SiC substrate increases by 8.15% while the optical output power of the FC-LEDs on patterned sapphire substrate improves 48% from the experimental results. According to the simulation data, the LEE enhancements of the FC-LEDs on patterned SiC and sapphire substrates cause the improvements of the light output power.