Nitride-based light-emitting diodes (LEDs) grown on different convex-patterned sapphire substrates are proposed and fabricated. The electrical and optical properties of these LEDs are discussed in detail. It is found that the LED with a ball-shape patterned sapphire substrate has the best crystalline quality and IV characteristic. On the other hand, on reducing total internal reflection, the LED with hexagonalshape patterned sapphire substrate (HPSS) has the best performance on output power and external quantum efficiency. In comparison to the LED without patterned substrate, the LED with HPSS has 175% and 165% enhancement on output power and external quantum efficiency, respectively.
- External quantum efficiency (EQE)
- Light-emitting diodes (LEDs)
- Patterned sapphire substrate (PSS)