1. Lab of Optoelectronic Technology for Low Dimensional Nanomaterials School of Chemistry and Chemical Engineering University of South China Hengyang 421001 China
2. Advanced Institute of Photonics Technology School of Information Engineering Guangdong University of Technology Guangzhou 510006 China
3. Department of Physics and Astronomy Uppsala University Box 516 Uppsala SE‐751 20 Sweden
4. School of Electrical and Electronic Engineering Wuhan Polytechnic University Wuhan 430023 China
5. The State Key Laboratory of Refractories and Metallurgy Key Laboratory for Ferous Metalurgy and Resources Utilization of Ministry of Education & Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steel making Faculty of Materials Wuhan University of Science and Technology Wuhan 430081 China