Scientists from SLAC, Stanford and Berkeley Lab grew sheets of an exotic material in a single atomic layer and measured its electronic structure for the first time. They discovered it’s a natural fit for making thin, flexible light-based electronics.
This diagram shows a single layer of MoSe2 thin film (green and yellow balls) grown on a layer of graphene (black balls) that has formed on the surface of a silicon carbide substrate. Scientists who made the material and measured details of its electronic structure discovered it’s a natural fit for making thin, flexible light-based electronics. (Yi Zhang/Stanford Institute for Materials and Energy Sciences and Advanced Light Source, Berkeley Lab)
In a study published December 22 in Nature Nanotechnology, the researchers give a recipe for making the thinnest possible sheets of the material, called molybdenum diselenide or MoSe2, in a precisely controlled way, using a technique that’s common in electronics manufacturing.
“We found the right recipe, and we provide it in the paper so people can develop it more for industrial purposes,” said Sung-Kwan Mo, a beam scientist at Lawrence Berkeley National Laboratory’s Advanced Light Source (ALS), where the material was made.
“Based on tests at the ALS and at Stanford, now we can say MoSe2 has possible applications in photoelectronic devices, such as light detectors and solar cells,” said Yi Zhang, a postdoctoral researcher who designed and built the equipment used to make the thin sheets, and the report’s first author. The material also has potential for novel types of electronics that are still in the future, he said. Zhang is affiliated with Berkeley Lab and the Stanford Institute for Materials and Energy Sciences, which is jointly run with SLAC National Accelerator Laboratory.
Single atomic sheets of MoSe2 have been generating a lot of scientific interest lately because they belong to a small class of materials that absorb light and glow with great efficiency.
But until now, no one had been able to make extremely thin layers of MoSe2 in significant quantities and directly observe the evolution of their electronic structure. This is important because a material’s electronic behavior can change fundamentally, and in useful ways, when its electrons are confined to such thin layers.