"Patterned materials open up the possibility of having two functionalities in a single material," said Professor Sokrates Pantelides from Vanderbilt University. "Of course, you can do such a thing by using two materials side by side, but patterned materials offer a whole range of new options for device designers."
Chalcogenides – 2D materials that contain sulphur, selenium or tellurium – are known for their widely varied optical, electrical and thermal properties and naturally form monolayers that can serve as blank slates that can be readily tailored for specific applications.
The researchers have shown that monolayers formed by two chalcogenides – platinum-selenium and copper-selenium – naturally combine with nanoscale precision into alternating triangles with different phases: metallic and semiconductor.
Because each phase has different electrical and chemical properties, the researchers claim two different types of molecules can bond to its surface, allowing it to perform two functions simultaneously.
"In general, 2D materials are 'functionalised' for specific applications by adsorbing different species of atoms or molecules on them or by embedding impurities in their otherwise perfect crystalline structure," Pantelides explained.
"Our new paper demonstrates a way to fabricate 2D materials that allows the two phases of the material to be functionalised independently."