Electron-Hole Liquid Formation in Monolayer Semiconductors at Room Temperature

Analogous to gas-to-liquid condensation in real particle systems, electronic excitations in semiconductors may also undergo liquification at high density and low temperature. An example of this quasiparticle condensation is the photoexcited state known as electron-hole liquid (EHL); a condensed degenerate electron-hole plasma. In the nearly 50 years since its discovery, EHL formation has been limited to cryogenic temperatures, and therefore outside the range of most practical applications. In contrast, 2D semiconductors are ideal candidates for high-temperature EHL formation due to their quantum confinement, reduced material screening, and long charge lifetime. We have recently discovered EHL in monolayer transition metal dichalcogenides (TMDs) that can be created above room temperature using less excitation power than a laser pointer. A description of this discovery and the process of EHL formation in monolayer TMDs will be presented.