Opening up a new direction! New diamond-graphite material, Chinese scientists break through technical barriers!

In the field of materials science, a new covalent diamond-graphite material has attracted widespread attention in the scientific community. This material not only combines the excellent properties of diamond and graphite, such as super hardness, extreme toughness and electrical conductivity, but also shows great research and development potential in the fields of superhard materials and electronic devices. Recently, a research team from the Shenyang National Research Center for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, made a breakthrough in ion chemical vapor deposition (CVD) technology, successfully prepared this new material, and conducted in-depth research on its growth mechanism and electronic properties. 

Based on plasma CVD technology, the team led by researcher Huang Nan successfully increased the plasma electron density to 2.7 times the original through a carefully designed confined ceramic sample stage, which activated carbon atoms and promoted their interaction with diamond and graphite. Form covalent linkage provides ample energy. Transmission electron microscopy observations show that specific crystal planes of diamond and graphite are covalently connected in a specific corresponding relationship. This interface structure is significantly different from the covalent diamond-graphite interface prepared by traditional high-temperature and high-pressure methods.

Further electron energy loss spectrum analysis showed that the electron density of graphite at the interface increased, showing the characteristics of sp2/sp3 carbon hybridization, which means that diamond and graphite formed a strong interaction at the covalent bond interface. Through first-principles calculations, the research team revealed how this strong interaction interface affects the transfer and distribution of electrons, thereby changing the electronic properties of the interfacial carbon, causing an abnormal increase in the state density of graphite near the Fermi level and introducing localized energy levels at the bottom of the conduction band of diamond.

This research not only reveals the growth mechanism of covalent diamond-graphite materials, but also demonstrates how to modulate the electronic properties of materials by precisely controlling the preparation process. The research results were published in the internationally renowned academic journal Advanced Functional Materials under the title of "Covalently-bonded diaphite nanoplatelet with engineered electronic properties of diamond" and were funded by the National Natural Science Foundation of China and other institutions.

Figure 1:The preparation routine and microstructure characterizations of covalently-bonded diaphite. 

Figure 2:Growth mechanism of the covalently-bonded diaphite in CVD. 

Figure 3:CL investigations on the electronic property of covalently-bonded diaphite. 

Figure 4:EELS investigations and DFT calculations on the electronic property of covalently-bonded diaphite. 

Industry experts said that this groundbreaking research not only provides new ideas for the development of diamond electronic devices, but also opens up a new direction for the future development of materials science. With the deepening of research, this new covalent diamond-graphite material is expected to show broad application prospects in many fields such as superhard materials, electronic devices, and energy storage.