Oak Ridge National Laboratory researchers serendipitously discovered when they automated the beam of an electron microscope to precisely drill holes in the atomically thin lattice of graphene, the drilled holes closed up. They expected the heat to make atoms easier to remove, but they saw the opposite effect.
“Graphene appeared impervious to the electron beam,” said Ondrej Dyck, who co-led the study with Stephen Jesse at ORNL’s Center for Nanophase Materials Sciences. Jesse added, “It heals locally, like the (fictitious) liquid-metal T-1000 in the movie Terminator 2: Judgment Day.”
Theory-based computations performed on the lab’s Summit supercomputer, led by ORNL’s Mina Yoon, explained the quasi-metal’s healing ability: Single atomic vacancies zip through the heated graphene until they meet up with other vacancies and become immobilized.
“Similar processes are likely to extend to other 2D materials,” Dyck said.
“Controlling such processes could help us realize graphene’s promise for quantum information science,” said Jesse.
The researchers are applying this new knowledge to guide creation of atomic-scale devices.
Reference
The role of temperature on defect diffusion and nanoscale patterning in graphene
Ondrej Dyck, Sinchul Yeom, Sarah Dillender, Andrew R. Lupini, Mina Yoon, Stephen Jesse
https://www.sciencedirect.com/science/article/pii/S0008622322007308?via=ihub
Waste polyamide-derived CQDs show continuous photoluminescence tuning from 308 to 552 nm through sequential defect-state engineering, with optical transition energies decreasing from 4.32 to 2.50 eV. @Christian Ebere Enyoh from Saitama University Carbon quantum dots (CQDs) are fluorescent carbon nanomaterials with potential applications in sensing, optoelectronics, displays, anti-counterfeiting, and environmental technologies. Their optical properties can be adjusted by modifying the carbon...
The researchers used circularly polarized light at normal incidence and found that helicity-dependent photocurrents appeared perpendicular to the crystal’s polarization but vanished when measured parallel to it, supporting a bulk origin of CPGE. @Institute of Science Tokyo The circular photogalvanic effect (CPGE), a phenomenon that generates helicity-dependent photocurrents in noncentrosymmetric materials, can originate purely from a crystal's internal structure without contribution from the...
Summary of gold nanoparticle growth programming in liposome based on localization of biomineralization peptide The position of biomineralization peptides within liposomes can influence how gold nanoparticles grow, reports a research team from Institute of Science Tokyo. Peptides localized at the membrane interface promote branched structures, while those confined to the liposome interior favor spherical nanoparticles. The findings offer a new strategy for controlling nanoscale reaction...
