1. State Key Laboratory on Integrated Optoelectronics; College of Electronic Science and Engineering; Jilin University; 2699 Qianjin Street Changchun 130012 P. R. China
2. Shanghai Keyan Phosphor Technology Co., Ltd.; Shanghai 201619 P. R. China
3. Department of Physics; Atmospheric Sciences and Geoscience; Jackson State University; Jackson MS 39217 USA