Researchers at Tokyo Metropolitan University have successfully wrapped gold atoms (Bind rows of metal atoms into nanofiber bundles) between individual fibers in bundles of transition metal chalcogenide nanofibers. By exposing the bundle to indium gas, rows of atoms can work between the strands to create unique nanostructures through bonding. Through simulations and resistivity measurements, individual packages have been shown to contain metallic elements, opening the way for applications such as flexible nanowires and nanocircuits.
Transition metal chalcogenide (TMC) atomic wires are nanostructures made of transition metals and group 16 elements such as sulfur, selenium and tellurium. They are able to assemble themselves into a variety of different types, putting them at the heart of the evolution of nanomaterials which is the subject of intense research in recent years. In particular, a class of 3D TMC structures has attracted special attention, which consists of bundles of TMC nanofibers with metal atoms connected between fibers, all of which form a well-defined network in its domain (see Figure 1). Depending on the choice of metal, the structure can become unimaginable. Furthermore, by softening the bundles, they can be transformed into flexible materials that conduct electricity: this makes TMC nanostructures ideal for use as wiring and nanocircuits. However, it is difficult to convert these structures into long fibers, which is necessary to study them well, and for nanotechnology applications.
A team led by Assistant Professor Yusuke Nakanishi and Associate Professor Yasumitsu Miyata investigated the method for synthesizing TMC nanostructures. In recent work (Bind rows of metal atoms into nanofiber bundles), they have shown that they can create long, thin TMC (metal-free) TMC at unprecedented length scales. Now, they’ve used a vapor-phase reaction to insert three thin layers of indium into thin layers of tungsten telluride. By exposing their long nanofibers to indium vapor under vacuum at 500 degrees Celsius, the metal indium atoms work through the gaps between the nanofibers that fill the bundle, forming lines (or is binding) of indium which binds the fiber together.
After producing a large number of TMC threads, they investigated the properties of their new nanowires. By examining the resistivity as a function of temperature, they showed in detail that each bundle behaves like a metal and thus conducts electricity. This agrees with the computer simulations and shows how well the structures are designed. Interestingly, they found that this structure is slightly different in large batches of bundled nanofibers, because the lines that converge in the middle rotate each nanofiber slightly around its axis.
This method is not limited to indium tungsten telluride, nor is this method. They hope that their work can spark a new chapter in the development of nanomaterials in their unique study.
Source: Tokyo Metropolitan University.
