1. Laboratory of Infrared Materials and Devices, The Research Institute of Advanced Technologies, Ningbo University, Ningbo, Zhejiang 315211, China
2. Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, D-04318 Leipzig, Germany
3. Key Laboratory of Photoelectric Detection Materials and Devices of Zhejiang Province, Ningbo, Zhejiang 315211, China