C3N—A 2D Crystalline, Hole‐Free, Tunable‐Narrow‐Bandgap Semiconductor with Ferromagnetic Properties

• DOI: 10.1002/adma.201605625
• Publication Date: 2017-02-27T12:52:42Z
• Authors: Siwei Yang; Wei Li; Caichao Ye; Gang Wang; He Tian; Chong Zhu; Peng He; Guqiao Ding; Xiaoming Xie; Yang Liu; Yeshayahu Lifshitz; Shuit‐Tong Lee; Zhenhui Kang; Mianheng Jiang
• Keywords: 02 engineering and technology; 0210 nano-technology

Graphene has initiated intensive research efforts on 2D crystalline materials due to its extraordinary set of properties and the resulting host of possible applications. Here the authors report on the controllable large‐scale synthesis of C3N, a 2D crystalline, hole‐free extension of graphene, its structural characterization, and some of its unique properties. C3N is fabricated by polymerization of 2,3‐diaminophenazine. It consists of a 2D honeycomb lattice with a homogeneous distribution of nitrogen atoms, where both N and C atoms show a D6h‐symmetry. C3N is a semiconductor with an indirect bandgap of 0.39 eV that can be tuned to cover the entire visible range by fabrication of quantum dots with different diameters. Back‐gated field‐effect transistors made of single‐layer C3N display an on–off current ratio reaching 5.5 × 1010. Surprisingly, C3N exhibits a ferromagnetic order at low temperatures (<96 K) when doped with hydrogen. This new member of the graphene family opens the door for both fundamental basic research and possible future applications.