Black phosphorus is a strong contender for building more energy-efficient transistors, according to a study released in the journal Nature Communications.

According to Thomas Szkopek, a McGill University electrical and computer engineering associate professor and senior author of the study, transistors are more efficient when they are made thin, with electrons moving within just two dimensions. Electrons in black phosphorus behave this way, suggesting that the material can help engineers address one of the biggest challenges in electronics: energy-efficient transistors.

This focus on thin materials for transistors was the result of researchers isolating and exploring graphene. At just as thick as an atom, the carbon layer displayed remarkable properties that showed the potential two-dimensional materials have for electronics. This prompted more studies on two-dimensional materials, one of which is black phosphorus. As a phosphorus form with similarities to graphite, it can be easily separated further into single-atom layers called phosphorene.

"Nothing gets thinner than a single layer of atoms," stated Szkopek.

There's growing interest in phospherene, however, because it has managed to overcome a lot of the challenges graphene was facing in electronics. For starters, graphene acts like metal. On the other hand, black phosphorus has natural semiconductor abilities, meaning it can be turned on or off without trouble.

To see how electrons moved in a transistor made out of phosphorus, the researchers performed experiments at the National High Magnetic Field Laboratory in Florida, the largest, highest-powered magnet lab in the world. The magnet laboratory is supported by the U.S. Department of Energy, the National Science Foundation and the State of Florida.

Szkopek explained that what's surprising is that electrons in phosphorus behaved two-dimensionally despite being several atoms thick. This finding has significance because it could simplify the manufacturing process for the material. However, at this point, no one knows yet how the material can be produced on a larger scale.

The researchers believe that there is still a long way to go before transistors as thick as single layers of atom will be included in commercial products but that they are at least a step closer toward that goal.

The study received funding support from the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs program, Le regroupement québécois sur les matériaux de pointe, the Fonds de recherche du Québec - Nature et technologies and the Canadian Institute for Advanced Research.

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