1. School of Integrated Circuits, Huazhong University of Science and Technology, Wuhan 430074, P. R. China
2. CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
3. Sysmo Technologies Co., Ltd, Beijing 100020, P. R. China
4. Research Institute of Huazhong University of Science and Technology in Shenzhen, Shenzhen 518000, P. R. China