Researchers reported that graphene nanoribbons with smooth closed edges can be produced by squashing carbon nanotubes.
Graphene is a potential material for future electronic devices. However, one of the major obstacles to the application of graphene in electronics and optoelectronics has been that two-dimensional graphene is a semimetal with the zero bandgap. A solution to this can be using one-dimensional graphene nanoribbons (GNRs) with a narrow width. The nano width GNRs of <10 nm are all semiconducting, and with a width of less than 5nm have a sizable bandgap, which can meet the application requirements of high-performance logic devices.
However, efficiently preparing such GNRs is difficult. The mobility and conductivity of GNRs are highly dependent on the degree of edge roughness due to edge scattering effects. Therefore, producing GNRs with smooth edges is very critical.
Researchers from Shanghai Jiao Tong University and Shanghai Jiao Tong University have reported that sub-10-nm-wide semiconducting graphene nanoribbons with atomically smooth closed edges can be produced by squashing carbon nanotubes using a high-pressure and thermal treatment.
Researchers used a diamond anvil cell (DAC) for the high-pressure treatment of carbon nanotubes (CNTs). The CNTs were loaded and sealed in a sample chamber in the centre of a pre-indented tungsten gasket that was then compressed between two diamond anvils. This squashes the CNTs into GNRs. The GNRs we get from this approach have atomically smooth, closed edges with only few defects.
“Comparing with the methods reported earlier, this new approach is capable of producing much narrower GNRs,” Changxin Chen, the first author and corresponding author of this work and a professor of electronic science and technology at Shanghai Jiao Tong University, said. “Moreover, the atomically smooth edges throughout the entire GNR can be achieved by our method, resulting in high material and device mobility.”
“Taking advantage of our method’s high yield, it is hopeful to scale up the synthesis by further using a multi-anvil apparatus or a large-volume press. Importantly, this method can also be extended to make other material-based nanoribbons from squashed nanotubes and to flatten other fullerene materials,” said Changxin Chen.
The work is described in the journal Nature Electronics.