Shanghai Institute of Microsystem And Information Technology makes breakthrough in the research of graphene single crystal throu
In 2011, the graphene team of Shanghai Microsystems Co., Ltd. started the work of epitaxial growth of graphene single crystals on a hexagonal boron nitride substrate and its performance characterization, and achieved a series of results. They mastered the graphene nucleation control (Carbon, 50, 329 (2012)), determined the orientation relationship between single crystals and substrates (ScientificReports, 3, 2666, (2013)), and used acetylene as a carbon source, which was innovative. Using silane as a catalyst, graphene single crystals with a crystal domain size of more than 20 μm were prepared by a chemical vapor phase epitaxy method. The growth rate was improved by two orders of magnitude compared with previous reports, and over 90% of graphene single crystals and boron nitride were obtained. The substrate is strictly oriented, exhibiting a ~14 nm two-dimensional superlattice structure caused by the Moiré fringes, and the typical room temperature Hall mobility of the prepared graphene exceeds 20,000 cm2/V.s.
Graphene is generally considered to be the most competitive electronic material for the continuation of Moore's Law in the post-silicon CMOS era due to its excellent electrical properties, superior thermal conductivity, and excellent mechanical properties. However, the electrical properties of graphene are greatly affected by the substrate, and the charge and phonon scattering greatly degrade the electrical properties of the graphene. Studies have shown that hexagonal boron nitride is an excellent substrate for graphene electronic devices due to its surface atomic leveling, no dangling bonds, and excellent insulating properties. The graphene single crystal grown directly on the surface of hexagonal boron nitride by chemical vapor deposition can avoid interface contamination and damage defects caused by physical transfer, and provide a material basis for further application in the field of integrated circuits. However, due to the lack of catalytic ability of the substrate, the growth of graphene single crystals directly on the surface of hexagonal boron nitride dielectrics has been a huge problem in the entire graphene research field. The gaseous catalytic method proposed in this study has been patented and can provide a new idea and technical solution for the preparation of high quality graphene single crystal films on dielectric substrates.
This work was funded by the major projects of the Ministry of Science and Technology, the Chinese Academy of Sciences and the Shanghai Municipal Science and Technology Commission.