As we appear to be reaching the limits of silicon, scientists are looking for new materials that can be used to load more transistors onto a chip. Although graphene gets plenty of attention for its incredible properties and many potential applications, it is not a great replacement for silicon because it lacks a band gap, which means it constantly conducts and leaks electricity.
Other 2D materials are better candidates, and the latest new material to capture scientists’ attention is a form of phosphorus, the highly reactive element that is used in match heads. Black phosphorus can be separated into single atomic layers and it stands out from graphene because it is a natural semiconductor that can be switched on and off. Earlier this year, researchers from the University of Minnesota proved that black phosphorus could be used for light-based communication. They demonstrated high-speed data communication on optical circuits made from black phosphorus, with better performance than similar graphene-based devices.
Now, researchers from McGill University and Université de Montréal published a study in Nature Communications that shows how black phosphorus can be used to help engineers design better transistors. “Transistors work more efficiently when they are thin, with electrons moving in only two dimensions,” says author Thomas Szkopek. “Nothing gets thinner than a single layer of atoms.”
To better understand the fundamental properties of black phosphorus, the researchers conducted experiments at the largest and highest-powered magnet laboratory in the world, Florida’s National High Magnetic Field Laboratory. They observed electrons’ behavior in a phosphorus transistor. Szkopek says, “What’s surprising in these results is that the electrons are able to be pulled into a sheet of charge which is two-dimensional, even though they occupy a volume that is several atomic layers in thickness.” This research could help engineers find a way to manufacture the emerging material on a larger scale, which could eventually lead to the commercialization of 2D transistors.
