Study of the effect of varies MQWs conditions on GaN-based LED grown on GaN substrate

• Main Authors: Shih-Wen Hung, 洪士文
• Other Authors: Fang-I Lai
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/u83533

碩士 === 元智大學 === 光電工程學系 === 103 === To improve the internal quantum efficiency and light extraction efficient of LEDs, which can be increased the external quantum efficiency effectively. Many researchers used pattern sapphire substrate (PSS) to improve the internal quantum efficiency and light extraction efficient of LEDs. However, growing high quality GaN on pattern sapphire substrates proves difficult because of the large lattice mismatch and large thermal mismatch between PSS and GaN. The main purpose of this thesis is study of the effect of varies multiple quantum well (MQWs) conditions grown on GaN substrate. Using the GaN substrate for homo-epitaxy can reduce the high defect density due to mismatched lattice constants and crystal defect caused by the different thermal expansion. And therefore improved the GaN based LED light emission efficiency by GaN substrate. Base on studies indicated that the LEDs grown on GaN substrates obtained a lower forward voltage and higher light output power. Also, the external quantum efficiency of LEDs grown on GaN substrates was improved. The efficiency droop phenomenon was reduced at high injection current.