1. Institute of Functional Nano & Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon‐Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China, Fax: 86‐512‐65882846
2. Center of Super‐Diamond and Advanced Films and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, China