Ding Guqiao's research group of State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences independently discovered new two-dimensional semiconductor quantum material C₃N. The related research paper "C₃N-a 2-Dimensional crystalline, hole-free, tunable-narrow-bandgap semiconductor with ferromagnetic properties" was published online in the top international academic journal "Advanced Materials" on February 28, 2017 (Siwei Yang, et al, Adv. Mater., 2017,DOI:1010.1002/adma.201605625; Paper link: Http://dx.doi.org/10.1002/adma.201605625).

    Yang Siwei, PhD candidate of the research group et al. successfully implemented the preparation of the single layer 2-dimensional new material using 2,3-diaminophenazine small molecule hydrothermal synthesis method. The material, a kind of graphene like cellular nonporous ordered structure composed of carbon and nitrogen atoms. is a new indirect bandgap semiconductor with the intrinsic bandgap of 0.39eV, which is tunable through nanometer size effect. And the theoretical calculation and experimental results are consistent. The FET device switching ratio based on single-layer C₃N thin films can achieve as high as 5.5 ×10¹⁰, with the carrier mobility up to 220 cm2V^-1s^-1. By tuning the size of theC₃N quantum dots, photoluminescence of about 400-900 nm can be achieved. It is worth noting that hole injection of the material can be achieved by hydrogenation, and long-range ferromagnetic process can be generated at temperatures below 96K. The presence of bandgap makes up for the defect of graphene without bandgap. Hydrogenated carrier injection provides a new means for regulating the electrical properties of the material, and the ferromagnetism indicates that the material system has rich physical connotations. The discovery adds a new member to family of carbon-based 2-dimensional materials, laying a foundation for exploring new physics and new devices based on the 2-dimensional new materials.

This study began in 2013. In January 2014, the laboratory successfully prepared the new material and completed the relevant theoretical analysis and characterization of the basic properties of the material. After repeated discussions in the submission process, the experimental results were supplemented many times and the paper was revised and improved, and finally accepted and published by the journal "Advanced Materials".

The study was supported by the National Science and Technology Major Project 02 of the Ministry of Science and Technology "Wafer grade graphene electronic materials and devices research" (Grant No. 2011ZX02707) and other projects. Research cooperation units include Soochow University, Zhejiang University, ShanghaiTech University, Fudan University and Israel Institute of Technology.

 Note: In April 2016, Jong-BeomBaek research group in Korea reported the research findings of the preparation of block multi-layer C3N using the hexa-aminobenzene by the high-temperature palladium catalyzed coupling carbonization method in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

               Fig. a and b: TEM image of micrometer scale single-layer C₃N thin film; c: Electron diffraction image of micrometer scale single-layer C₃N thin film; d: 15N-NMR spectrum of micrometer scale single-layer C₃N thin film; e: Structure diagram of C₃N.