Researchers from Brown University in the US have developed a way to make nanoribbons and nanoplates from silicon telluride. The resulting materials are pure p-type semiconductors that have the potential to be used in a variety of electronic and optical devices. The team also notes the layered structure of the nanoribbons could allow them to take up lithium and magnesium, meaning they could be used to make electrodes for batteries.
Kristie Koski, assistant professor of chemistry at Brown, and her team synthesised the materials through vapour deposition in a tube furnace. Different structures can be made by varying the furnace temperature and using different substrate treatments. By tweaking the process, the researchers made nanoribbons that are about 50 to 1000nm wide and about 10µm long. They also made nanoplates flat on the substrate and standing upright.
"We see the standing plates a lot," Koski said. "They're half hexagons sitting upright on the substrate. They look a little like a graveyard."
Each shape has a different orientation of the material's crystalline structure, resulting in different properties and suiting them to different applications.
The researchers also showed the material can be 'doped'. In this case, the researchers showed that silicon telluride can be doped with aluminum when grown on a sapphire substrate. This could, for example, change the material from a p-type semiconductor to an n-type.
While the materials are not particularly stable, Koski says that can be remedied by oxidising the material, then baking off the tellurium, leaving a coating of silicon oxide.
The team now plans to continue testing the material's electronic and optical properties. "We think this is a good candidate for bringing the properties of 2D materials into the realm of electronics," Koski concluded.
