1. Key Laboratory of Multifunctional Materials and Structures Ministry of Education School of Electronic Science and Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China
2. School of Electronic and Information Engineering Hangzhou Dianzi University Hangzhou 310018 China
3. Micro-optoelectronic Systems Laboratories Xi'an Technological University Xi'an Shaanxi 710032 China