1. School of Microelectronics, Xidian University, Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xi'an 710071, China
2. Graduate Institute of Electronics Engineering, National Taiwan University, 10617 Taipei, Taiwan
3. Graduate Institute of Photonics and Optoelectronics, National Taiwan University, 10617 Taipei, Taiwan and Laboratory of Optoelectronic Materials and Detection Technology, Guangxi Key Laboratory for the Relativistic Astrophysics, College of Physics Science and Technology, Guangxi University, Nanning 530004, China
4. Graduate Institute of Electronics Engineering, National Taiwan University, 10617 Taipei, Taiwan and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, 10617 Taipei, Taiwan