July 13, 2020—Researchers at Columbia Engineering and Montana State University report today that they have found that placing sufficient strain in a 2-D material—tungsten diselenide (WSe2)—creates localized states that can yield single-photon emitters. Using sophisticated optical microscopy techniques developed at Columbia over the past three years, the team was able to directly image these states for the first time, revealing that even at room temperature they are highly tunable and act as quantum dots, tightly confined pieces of semiconductors that emit light.