When it originally developed phosphorene in 2014, the material was passivated by encasing it in a layer of alumina. But the latest work means the passivation layer is now thin enough to leave access to the material’s surface.
“If it’s going to be useful for applications such as sensors, then whatever you want to detect needs to be able to interact with the material,” said Professor Mark Hersam. “The thick layer of aluminum oxide prevented any atmospheric species from reaching the phosphorene surface, so it could not be used as a detector.”
The team believes the single molecule thick layer might even increase phosphorene’s potential: not only does the layer prevent phosphorene from degrading, but it also improves its electronic properties.
“The chemistry influenced the flow of charge through phosphorene,” Prof Hersam said. “We achieved improvement in charge mobility, which is related to the speed of the transistor, and how well it switches in an integrated circuit.”
Now the team has created a stable version of phosphorene, the next step is to create optimised devices based on phosphorene and compare them to devices made with alternative materials. “We can imagine many possibilities,” Prof Hersam concluded. “The future will teach us exactly where phosphorene has a competitive advantage.”