1. Faculty of Mathematics and PhysicsHuaiyin Institute of Technology Huai׳an 223003 P. R. China
2. College of Physics Optoelectronics and EnergySoochow University Suzhou 215006 P. R. China
3. Centre of Super‐Diamond and Advanced Films (COSDAF)City University of Hong Kong Kowloon Hong Kong P. R. China
4. Department of Materials Science and EngineeringMonash University Victoria Clayton 3800 Australia