1. Soochow University; School of Physical Science and Technology and Jiangsu Key Laboratory of Thin Films; 333 Ganjiang Road Suzhou 215006 PR China
2. Nanyang Technological University; School of Materials Science and Engineering; 50 Nanyang Avenue Singapore 639798 Singapore
3. Nanjing University; Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures; 22 Hankou Road Nanjing 210093 PR China