Over the years, finding a reliable way to prepare horizontal arrays of carbon nanotubes of the same structure is a major problem for scientists. Recently, Prof. Zhang Jin from the School of Chemistry and Molecular Engineering of Peking University and the Nano-Chemistry Research Center led the task group to develop a new method to synthesize a horizontal array of carbon nanotubes of the same structure with a purity of up to 90%. The "Nature" magazine published on the 15th published this important result online.
Carbon nanotubes (CNTs) are considered to have the greatest potential to replace silicon for the next generation of microelectronic devices because of their superior mechanical, electrical and thermal properties. Carbon nanotubes can be regarded as being formed by curling a graphite sheet, but its synthesis process does not involve curling at all, but is formed by catalyzing chemical vapor deposition on the surface of the catalyst particles. The catalyst not only provides a support structure but also catalyzes the decomposition of carbon-hydrogen bonds into carbon atoms to form carbon nanotubes.
In 2015, the team of Zhang Jin discovered that specific carbon nanotubes can be synthesized using solid carbide catalysts. This time, they developed a new method of epitaxial growth using the symmetry matching of carbon nanotubes and catalysts. Through the thermodynamic control of carbon nanotube nucleation efficiency and the kinetic control of the growth rate, the structure was realized as a chiral index ( Enrichment growth of 2m,m) CNT arrays. They used molybdenum carbide as a catalyst to prepare a horizontal array of metallic carbon nanotubes with a purity of 90% and a chiral index (12,6) and a density of 20 filaments/micron. They also used tungsten carbide as a catalyst to prepare semiconducting carbon nanotube horizontal arrays with a chiral index (8,4), and the purity was 80%. The theory predicts that the purity of this method can reach 99%, showing that there is still much room for development.
Professor Zhang Jin said that the same structure of semiconducting carbon nanotubes horizontal array is very suitable for the production of carbon nanotube transistors, they will continue to improve the purity in the future, and the selective preparation of other types of carbon nanotube structure. (Reporter Nie Cuirong)
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