1. Laboratory of Infrared Materials and Devices The Research Institute of Advanced Technologies Ningbo University Ningbo 315211 P. R. China
2. Zhejiang Key Laboratory of Photoelectric Materials and Devices Ningbo 315211 P. R. China
3. Engineering Research Center for Advanced Infrared Photoelectric Materials and Devices of Zhejiang Province Ningbo 315211 P. R. China
4. Shenzhen Key Laboratory of Advanced Thin Films and Applications Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen 518060 P. R. China