1. Institute of Photo-electronic Thin Film Devices and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China
2. Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, United States
3. MIIT Key Laboratory of Thermal Control of Electronic Equipment, School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, China