Optimized double-sided hemispherical pattern design on patterned sapphire substrate for flip-chip GaN-based LED

In order to improve the light extraction efficiency of GaN-based light-emitting diodes(LEDs), a model was built to optimize the double-sided hemispherical patterned sapphire substrate(PSS) for highly efficient flip-chip GaN-based light LEDs,and an optical simulation was conducted to study how light extraction efficiency changed with the change in the parameters of the unit hemisphere for flip-chip LEDs fabricated on hemispherical PSS. Results show that the light extraction efficiency of flip-chip LEDs can be enhanced by the optimized hemispherical PSS by over 50.8% and is approximately 115.3% higher than that of flip-chip LEDs with non-PSS when the radius is 3m and the distance is 7m. This results confirm the high efficiency and excellent capability of the optimized hemispherical PSS pattern to improve LED efficacy.