1. School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
2. Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, Taiwan
3. Department of Electrical Engineering and Institute of Photonics and Optoelectronics Engineering, National Taiwan University, Taipei, Taiwan
4. Department of Metallurgical and Materials Engineering, The University of Alabama, Tuscaloosa, Alabama, United States
5. Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing, China