Electroluminescence properties of InGaN/GaN Multiple Quantum Well Light-Emitting Diodes

• Main Authors: Tzung-Shian Yang, 楊宗憲
• Other Authors: Tai-Yuan Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/97400109194095846415

碩士 === 國立臺灣海洋大學 === 光電科學研究所 === 97 === Current-voltage (I-V) and luminescence-current (L-I) measurements were performed to investigate the effect the electron blocking layer (EBL) on the electrical and optical properties of the InGaN/GaN multiple quantum wells (MQWs) based blue light emitting diodes(LEDs). The results of I-V measurements show that the LEDs with EBL have the smaller forward voltage and the higher reverse voltage than that of the LEDs without EBL. All these behaviors of the LEDs with EBL layer indicate that LEDs with EBL have the less threading dislocation density in accordance with a lot of previous reports. According to the results of L-I measurements, it is found that there are superlinear, linear and sublinear dependence of electroluminescence (EL) from the LEDs with and without the EBL structures. The superlinear dependence of EL dominates at the low injection current regions (0.01~0.2mA for LEDs with EBL, 0.01~2mA for LEDs without EBL). In the intermediate injection current regions, the linear dependence of EL becomes the dominant behavior for the LEDs studied here(0.2~30mA for LEDs with EBL, 2~10mA for LEDs without EBL). As the injection current are increased further, the sublinear dependence of EL dominates the L-I relation of the LEDs( >30mA for LEDs with EBL, >10mA for LED without EBL). All these phenomena can be understood by considering the possible better crystallinity and the electron blocking ability due to the p-AlGaN EBL in the LEDs.