Atomic scale nanowires can now be produced to a large extent

(a) Illustration of TMC nanowire (b) Precipitation of chemical vapors. The ingredients evaporate in a hydrogen / nitrogen atmosphere and are allowed to settle and self-assemble on the substrate. Reprinted with permission of ref. 1 credit: Copyright 2020 American Chemical Society (ACS)

Researchers from the Metropolitan University in Tokyo have discovered a way to independently assemble nanowires from transition metal chalcogenides, using chemical precipitation. By changing the substrate where the wires are formed, they can adjust the way these wires are arranged, from aligned configurations of atomically thin sheets to random bundle networks. This paves the way for the industrial introduction of next-generation industrial electronics, including energy collection, and transparent, efficient, even flexible devices.

Electronics are concerned with reducing things – for example, smaller features on a chip mean more computing power in the same amount of space and greater efficiency, necessary to meet the increasingly demanding demands of modern IT infrastructure driven by machine learning and artificial intelligence. And as devices shrink, the same demands are placed on the intricate wiring that connects everything. The ultimate goal would be a wire only one or two atoms thick. Such nanowires would begin to use a completely different physics as the electrons traveling through them behave more and more as if they were living in a one-dimensional rather than a three-dimensional world.

In fact, scientists already have materials such as carbon nanotubes and transition metal chalcogenides (TMCs), mixtures of transition metals, and group 16 elements that can self-assemble into nanowires of atomic proportions. The problem is that they make them long and extensive enough. The way to mass-produce nanowires would be to change the game.

Now the team led by Dr. Hong En Lim and associate professor Yasumitsu Miyata of the Metropolitan University of Tokyo devised a way to make long nanowire wires from telluride transition metal on an unprecedented scale. Using a process called chemical precipitation (CVD), they found that TMC nanowires can be assembled in different layouts, depending on the surface or substrate they use as a template. Examples are shown in Figure 2; u (a), nanowires grown on a silica / silica substrate form a random network of beams; in (b), the wires are assembled in a set direction on a sapphire substrate, following the structure of the underlying sapphire crystal. By simply changing the breeding site, the team now has access to centimeter-sized wafers covered with the desired layout, including single-layer layers, double-layer layers, and bundle networks, all with different applications. They also found that the structure of the wires themselves was highly crystalline and ordered and that their properties, including excellent conductivity and behavior like 1D, matched those found in the theoretical predictions.

Atomic scale nanowires can now be produced to a large extent

(a) Scanning electron microscopic image of nanowires grown on a silica / silica plate. (b) Image of atomic force microscopy of nanowires grown on a crystalline sapphire substrate. (c) Scanning a portable electron microscopy image of aligned wires. (d) Scanning the electron microscopy image of the transmission of a single TMC nanowire, viewed from the end, with an illustration of the structure. Reprinted with permission of ref. 1 credit: American Chemical Society (ACS)

Having large amounts of long high-crystalline nanowires will certainly help physicists to deeper characterize and study these exotic structures. Most importantly, it is an exciting step towards seeing the real applications of atomically thin wires, in transparent and flexible electronics, ultra efficient devices and energy collection applications.

Atomic scale nanowires can now be produced to a large extent

(left) (a) Illustration of different forms of TMC assembled on substrates. Transmission electron microscopy scanning of cross-sectional images of (b) single-layer nanowires, (c) double-layer nanowires, and (d) portable electron microscopy images of 3D beams. Reprinted with permission of ref. 1 credit: American Chemical Society (ACS)

2-D to 1-D: atomic quasi ‘1-D’ wires using carbon nanotube templates

More information:
Hong En Lim et al, Growth of wavy scales of one-dimensional nanowires of telluride transition metal, Nano words (2020). DOI: 10.1021 / acs.nanolett.0c03456

Provided by Tokyo Metropolitan University

Citation: Atomic scale nanowires can now be produced at the scale (2020, December 24) downloaded on December 24, 2020 from

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