Optical and Electrical Characteristics of GaN-based Blue LEDs after Low-current Stress
GaN계 청색 발광 다이오드에서 저전류 스트레스 후의 광 및 전기적 특성 변화

Seo-Hee Kim, Joo-Sun Yun, Dong-Soo Shin, Jong-In Shim
2012 Korean Journal of Optics and Photonics  
ㆍ윤주선 2 ㆍ신동수 1 † ㆍ심종인 2 1 한양대학교 응용물리학과 우 426-791 경기도 안산시 상록구 사3동 2 한양대학교 전자통신공학과 우 426-791 경기도 안산시 상록구 사3동 (2012년 3월 2일 받음, 2012년 4월 4일 수정본 받음, 2012년 4월 10일 게재 확정) c-plane 사파이어 기판에서 성장된 1 mm 2 대면적 InGaN/GaN 다중양자우물 청색 발광 다이오드의 스트레스 전후의 전기적, 광학적 특성 변화를 분석하였다. 스트레스 실험은 샘플 칩을 TO-CAN에 패키징하여 50 mA의 전류를 200시간 동안 인가하여 We analyzed the changes in electrical and optical characteristics of 1 mm 2 multiple-quantum-well (MQW) blue LEDs grown on a c-plane sapphire substrate after a stress test. Experiments
more » ... st. Experiments were performed by injecting 50 mA current for 200 hours to TO-CAN packaged sample chips. We selected the value of injection current for stress through the junction-temperature measurement by using the forward-voltage characteristics of a diode to maintain a sufficiently low junction temperature during the test. The junction temperature at the selected injection current of 50 mA was 308 K. Experiments were performed under the assumption that the average junction temperature of 308 K did not affect the characteristics of the ohmic contact and the GaN-based materials. Before and after the stress test, we measured and analyzed current-voltage, light-current, light distribution on the LED surface, wavelength spectrum and relative external quantum efficiency (EQE). After the stress test, it was observed experimentally that the optical power and the relative EQE decreased. We theoretically investigated and experimentally proved that these phenomena are due to the increased nonradiative recombination rate caused by the increased defect density.
doi:10.3807/kjop.2012.23.2.064 fatcat:humottjzizeynj4yiktxghpgpm