World\'s thinnest nanowires created by Vanderbilt grad student

A Vanderbilt doctorate student has found a way to construct the world's thinnest nanowire -- at just three atoms wide -- using a finely focused beam of electrons. Junhao Lin, who has been conducting his research as a visiting scientist at Oak Ridge National Laboratory (ORNL), was able to create wiring out of atomic monolayers of transition-metal dichalcogenides, a special family of semiconducting materials. A monolayer is the thinnest possible form for solid objects -- like a single sheet of interconnected atoms. Monolayers are of great interest (and value) to electronic engineers and other scientists, as they offer incredible strength and flexibility properties, as well as transparency and high electron mobility. Lin's discovery is another giant step forward in realizing their potential. "This will likely stimulate a huge research interest in monolayer circuit design," Lin said. "Because this technique uses electron irradiation, it can in principle be applicable to any kind of electron-based instrument, such as electron-beam lithography." To put things in perspective: the microscopic wires currently used in modern integrated circuits are a thousand times bigger than the nanowires Lin was able to fabricate. Lin carved the wires using an a tiny beam of electrons -- with help from his ORNL mentor Wu Zhou. "Junhao used a scanning transmission electron microscope (STEM)," Zhou explained, "that is capable of focusing a beam of electrons down to a width of half an angstrom (about half the size of an atom) and aims this beam with exquisite precision." Beyond enabling the wiring of even smaller, more durable transistors and flash memory drives, the greater potential for Lin's nanowires and monolayer technology is not entirely clear. But the possibilities are exciting. "If you let your imagination go," said Sokrates Pantelides, Lin's adviser at Vanderbilt, "you can envision tablets and television displays that are as thin as a sheet of paper that you can roll up and stuff in your pocket or purse." Lin's discovery was detailed this week in the journal Nature Nanotechnology.