Pure metal nanowires (NWs) are nanomaterials that have unique characteristics, making them advantageous for a variety of applications. However, a major barrier to their use in contemporary electronics has been the absence of a dependable method for mass production. Researchers have recently made strides in the mass production of aluminum NWs. This growth methodology could potentially be adapted for other metals, thereby eliminating current production limitations and signaling a new phase in nanotechnology.
A research team from Nagoya University in Japan has developed a novel method for creating these minuscule metal nanowires (NWs), which are anticipated to play a crucial role in next-generation electronics. Findings from their study indicate a path toward the mass production of pure metal NWs, addressing a significant hindrance in their applications. This innovative technique is expected to improve the manufacturing process for electronics, including circuits, LEDs, and solar panels. Their research was published in Science.
Producing NWs in large quantities has proven difficult due to the challenges of scaling up production while ensuring quality and purity. NWs are incredibly tiny, necessitating the movement of atoms—the fundamental building blocks of matter—usually in a gaseous state. However, working with metals in this manner has proven challenging, thereby limiting the availability of these essential electronic components.
To tackle this issue, a team led by Yasuhiro Kimura from the Nagoya University Graduate School of Engineering utilized atomic diffusion in a solid state that was enhanced through ion beam irradiation to generate aluminum NWs from single crystals.
Atomic diffusion refers to the movement of atoms or molecules from regions of high concentration to those of low concentration, facilitated by heat-induced stress changes. By applying ion beams to irradiate the crystal grains within the thin aluminum film, they enlarged the surface layer grains. This manipulation altered the stress distribution and directed atomic movement, effectively supplying the necessary atomic material for NW growth in designated areas. When heated, atoms flowed upward through the gradient from smaller grains at the bottom to larger ones at the top, leading to mass production of NWs.
Kimura stated, “We increased the density of aluminum NWs from 2×105 NWs per square cm to 180×105 per square cm. This accomplishment paves the way for bottom-up methods of growing metal NWs, which have previously only been achieved by chance and in small amounts. Moreover, this technique can be adapted for other metals as well.”
The aluminum NWs produced are expected to be valuable as nanocomponents in sensing devices and optoelectronics due to their exceptional properties, such as a large surface area, impressive mechanical traits from their single crystal composition, and their resilience to natural oxidation.
Kimura elaborated, “We achieved the mass production of tree-like metallic NWs using just three essential processes: thin film deposition on a substrate, ion beam irradiation, and heating. Our method addresses the pressing need for mass production techniques, particularly for high-performance nanodevices like gas sensors, biomarkers, and optoelectronic components.”
