1. New Energy Technology Engineering Laboratory of Jiangsu Province & School of Science, Nanjing University of Posts and Telecommunications
2. Nanjing 210023
3. China
4. Department of Physics, University of Illinois at Urbana-Champaign
5. Urbana
6. School of Electronic and Optical Engineering, Nanjing University of Science and Technology
7. Nanjing
8. Holonyak Micro and Nanotechnology Lab, University of Illinois at Urbana-Champaign
9. National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University
10. Nanjing 210093