1. Key Laboratory of Photonics Technology for Information, Key Laboratory
for Physical Electronics and Devices of the Ministry of Education,
School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, P. R. China
2. Department of Biomedical Engineering, School of Life Science and
Technology, Xi’an Jiaotong University, Xi’an 710049, P. R. China
3. Departmen of Microelectronics, School of Electronic and
Information Engineering, Xi’an Jiaotong University, Xi’an 710049, P. R. China
4. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States