Hyperspectral Nanoimaging of 2D Materials

Yohannes Abate works with nano optic technology to investigate 2D heterostructures. (Source: A. Davis, Tucker, UGA)

When we think about the links to the future – the global transition to solar and wind energy, tactile virtual reality or synthetic neurons – there’s no shortage of big ideas. It’s the materials to execute the big ideas – the ability to manu­facture the lithium-ion batteries, opto-electronics and hydrogen fuel cells – that stand between concept and reality. Enter two-dimensional materials, the latest step in inno­vation. Consisting of a single layer of atoms, two-dimensional materials like graphene and phos­phorene exhibit new properties with far-reaching potential. With a capability to be combined like Lego bricks, these materials offer connections to future products, including new means to convey both power and people, with more-efficient energy trans­mission, and solar- and wind-powered vehicles on roads and in skies.

A study led by University of Georgia researchers announces the success­ful use of a new nano­imaging technique that will allow researchers to test and identify these materials in a compre­hensive way at the nanoscale for the first time. Now, there’s a way to experiment with new materials for our big ideas at a really, really small scale. “Funda­mental science – small-scale electrical conduc­tivity, light emission, structural changes – happen at the nanoscale,” said Yohannes Abate, Susan Dasher and Charles Dasher MD Professor of Physics in the Franklin College of Arts and Sciences. “This new tool allows us to visua­lize all of this combined at unpre­cedented speci­ficity and reso­lution.”

“Since we cannot see atoms with tradi­tional methods, we needed to invent new tools to visualize them,” he said. The hyper­spectral imaging technique allows scientists to inspect electrical properties, optical proper­ties, and the mechanical properties at the funda­mental length scale, simul­taneously. The researchers created a one-atom thick sheet of two kinds of semi­conductors stitched together, similar to assembling an atomic Lego, with properties not found in tradi­tional thick materials. With single-atom-thick crystals, each atom is literally exposed on the surface, combining atomic properties that result in new properties.

“At the heart of materials science is the need to understand funda­mental properties of new materials, otherwise it is impossible to take advantage of their unique properties,” Abate said. “This technique puts us one step closer to being able to use these materials for a number of potential appli­cations.” Those include various forms of elec­tronics or light-emitting systems appli­cations. How to verify the effect of very small changes in atomic composition, conduc­tivity and light response of single-atom-thick materials simul­taneously has been the challenge until now, Abate said.

Nobel Prize-winning physicist Richard Feynman, who envisioned nano­technology as early as the 1960s, predicted that as scientists became able to choose and replace certain kinds of atoms, they would able to fabricate prac­tically any imaginable material. “More than half a century later, we’re not there yet, but where we are, we can visua­lize them, and at that scale there are new issues that can arise and we have to understand those properties as a part of under­standing the large scale material properties, before we can use them,” Abate said. (Source: UGA)

Reference: A. Fali et al.: Photodegradation Protection in 2D In-Plane Heterostructures Revealed by Hyperspectral Nanoimaging: The Role of Nanointerface 2D Alloys, ACS Nano, online 19. January 2021; DOI: 10.1021/acsnano.0c06148

Link: Dept. of Physics and Astronomy, University of Georgia, Athens, USA

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