Invariable optical properties of phosphor-free white light-emitting diode under electrical stress

• Published in: Chinese physics B 2010-10, Vol.19 (10), p.520-524
• Main Authors: Hao, Long, Hao, Fang, Sheng-Li, Qi, Li-Wen, Sang, Wen-Yu, Cao, Jian, Yan, Jun-Jing, Deng, Zhi-Jian, Yang, Guo-Yi, Zhang
• Format: Article
• Language: English
• Subjects: 光学性能; 反向漏电流; 电应力; 白光发光二极管; 白色发光二极管; 荧光粉; 透射电子显微镜; 金属有机化学气相沉积法
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/19/10/107307

This paper reports that a dual-wavelength white light-emitting diode is fabricated by using a metal-organic chemical vapor deposition method. Through a 200-hours＇ current stress, the reverse leakage current of this light-emitting diode increases with the aging time, but the optical properties remained unchanged despite the enhanced reverse leakage current. Transmission electron microscopy and cathodeluminescence images show that indium atoms were assembled in and around V-shape pits with various compositions, which can be ascribed to the emitted white light. Evolution of cathodeluminescence intensities under electron irradiation is also performed. Combining cathodeluminescence intensities under electron irradiation and above results, the increase of leakage channels and crystalline quality degradation are realized. Although leakage channels increase with aging, potential fluctuation caused by indium aggregation can effectively avoid the impact of leakage channels. Indium aggregation can be attributed to the mechanism of preventing optical degradation in phosphor-free white light-emitting diode.