Quantum mechanics

Materials science

Electric field

Silicon

Physics

Semimetal

Condensed matter physics

Ambipolar diffusion

Electron

Monocrystalline silicon

Optoelectronics

Conductance

Science

We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

Electric Field Effect in Atomically Thin Carbon Films