https://www.sciencedaily.com/releases/2020/01/200127164333.htm

Two-dimensional materials are atomically thin, the most well-known being graphene, a single-atom-thick layer of carbon atoms.

"People have struggled to make these 2D materials without defects," said Mauricio Terrones, Verne M. Willaman Professor of Physics, Penn State. "That's the ultimate goal. We want to have a 2D material on a four-inch wafer with at least an acceptable number of defects, but you want to evaluate it in a quick way."