1. Suzhou Key Laboratory for Nanophotonic and Nanoelectronic Materials and its Devices, School of Materials Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China
2. State Key Laboratories of Transducer Technology, Shanghai 200050, P. R. China
3. School of Electronic & Information Engineering, Suzhou University of Science and Technology, Suzhou 215009, Jiangsu Province, China
4. Key Laboratory for Thin Film and Microfabrication of the Ministry of Education, Department of Micro/Nano Electronics, School of Electronics, Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China