New progress in chemical doping and physical properties of graphene at semiconductors

Graphite intercalation compounds have been widely used in electrodes, electrical conductors, superconductors, and batteries since they were discovered in 1841. However, conventional graphite intercalation compounds are difficult to apply to nanodevices because of their thickness and large size limitations. On the other hand, graphene has significant potential applications in nanoelectronics and optoelectronic devices. Increasing its carrier concentration and mobility has always been one of the goals that fundamental physics and device application research areas have sought to address. If the graphene intercalation compound material can be formed by inserting an atomic or molecular layer between graphene layers, the physical and chemical properties of the graphite intercalation compound can be combined with the potential application of the graphene in nanoelectronics and optoelectronic devices. At the same time, due to the size and thickness limitations of graphene, X-ray diffraction, an important technique traditionally used to characterize the basic properties of graphite intercalation compounds, is difficult to apply to characterize graphene intercalation compounds. Therefore, new characterization methods must be explored to study these insertions. Layer compound.

Under the support of the Ministry of Science and Technology's major scientific research program and the National Natural Science Foundation of China, the Research Group of the State Key Laboratory of Semiconductor Superlattice Semiconductors of the Chinese Academy of Sciences Tan Pingheng and the team of Dr. Ferrari of the University of Cambridge in the United Kingdom have cooperated to use ferric chloride as a plug. Layering agents successfully synthesize graphene intercalation compounds with more than one layer of first order. By controlling the reaction conditions and the post-treatment manner, the graphene intercalation compound synthesized basically achieves complete doping of the graphene, and the hole concentration can reach 5.85.8×10 14 cm −2 . At the same time, Raman spectroscopy was used to systematically characterize the intercalation order, inter-layer decoupling and stability of the prepared compounds.

The results show that each layer of graphene after intercalation shows the behavior of monolayer graphene under heavy doping, and the prepared intercalation compound is quite stable. On this basis, the team also proposed a new method for the detection of heavily doped graphene Fermi energy levels with multi-wavelength Raman spectroscopy.

Some of the research results of this study were published in the form of Article on the American Chemical Journal (J. Am. Chem. Soc., 2011, 133(15), pp 5941-594). This study is of great significance for the synthesis of various graphene intercalation compounds and the study of the physical and chemical properties of the corresponding heavily doped graphene.