1. Department of Materials Science and Engineering, and Center for Functional Photonics (CFP), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region, P. R. China
2. Department of Materials Science and Engineering, Southern University of Science and Technology, No. 1088 Xueyuan Road, Shenzhen 518055, Guangdong, P. R. China
3. State Key Laboratory of Electrical Insulation and Power Equipment, Center of Nanomaterials for Renewable Energy (CNRE), School of Electrical Engineering, Xi’an Jiaotong University, Xi’an 710049, P. R. China
4. School of Energy and Environment, and Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong Special Administrative Region, P. R. China