Analyses of light extraction efficiency in GaN-based LEDs grown on patterned sapphire substrates

作者：Xu C.; Yu T.; Yan J.; Yang Z.; Li X.; Tao Y.; Fu X.; Chen Z.; Zhang G.

来源：Physica Status Solidi (C) Current Topics in Solid State Physics, 2012, 9(3-4): 757-760.

• GaN
• LEDs
• Light extraction efficiency
• Patterned sapphire substrate

The GaN-based LEDs external quantum efficiency (EQE) is significantly improved by using the patterned sapphire substrate (PSS) technique. The enhancements in the light extraction efficiency (LEE) and the internal quantum efficiency (IQE) were evaluated based on a rate equation analysis of EQE versus the square root of the light-output power (EQE-√P) curves. The estimated enhancement in the LEE was much larger than that in the IQE. The detailed mechanism of improving the LEE by PSS technique was investigated using Monte-Carlo ray tracing simulation. The LEE increased with the pattern height, and tended to be saturated when the height was over 1.5 μm. These results indicate that the improved light output power of GaN-based LEDs on PSS is mainly due to the enhancement in LEE.

• 出版日期2012
• 单位北京大学