Tokyo Metropolitan University Focuses On TMC Nanostructures

Scientists from the Tokyo Metropolitan University (TMU) – led by Assistant Professor Yusuke Nakanishi and Associate Professor Yasumitsu Miyata – have made a significant breakthrough in synthesis techniques for TMC nanostructures. Transition metal chalcogenides (TMCs) are nanostructures consisting of a transition metal and a group 16 element – such as sulfur, selenium, and tellurium. They are capable of self-assembling into a wide range of structures with different dimensionality and potential uses.

A specific class of 3D TMC structures has been of particular interest – consisting of bundles of TMC nanofibers held together by metallic atoms in between the fibers, all forming a well-ordered lattice in its cross-section. The structure can be made to become a superconductor – given the choice of metal – and, when the bundles are sufficiently thin, they can be made into flexible structures that conduct electricity, making them excellent candidates for use as wiring in nanocircuitry. 

Previously, researchers have been challenged in making these structures into the long, thin fibers that are required. The team at TMU successfully threaded atoms of indium metal in between individual fibers in bundles of transition metal chalcogenide nanofibers. By exposing the bundles to indium vapor under vacuum at 500 degrees Celsius, rows of atoms were able to make their way in between the fibers to create a unique nanostructure via intercalation. Through simulations and resistivity measurements, individual bundles were shown to have metallic properties, paving the way for application as flexible nanowires in nanocircuitry. The technique was found to not only be limited to indium and tungsten telluride, nor to this particular structure.