MoS2 transistors with 1-nanometer gate lengths

A flatter route to shorter channels High-performance silicon transistors can have gate lengths as short as 5 nm before source-drain tunneling and loss of electrostatic control lead to unacceptable leakage current when the device is off. Desai et al. explored the use of MoS2 as a channel material, given that its electronic properties as thin layers should limit such leakage. A transistor with a 1-nm physical gate was constructed with a MoS2 bilayer channel and a single-walled carbon nanotube gate electrode. Excellent switching characteristics and an on-off state current ratio of ∼106 were observed. Science, this issue p. 99 Molybdenum disulfide transistors with carbon nanotube gate electrodes have channel lengths below the silicon scaling limit. Scaling of silicon (Si) transistors is predicted to fail below 5-nanometer (nm) gate lengths because of severe short channel effects. As an alternative to Si, certain layered semiconductors are attractive for their atomically uniform thickness down to a monolayer, lower dielectric constants, larger band gaps, and heavier carrier effective mass. Here, we demonstrate molybdenum disulfide (MoS2) transistors with a 1-nm physical gate length using a single-walled carbon nanotube as the gate electrode. These ultrashort devices exhibit excellent switching characteristics with near ideal subthreshold swing of ~65 millivolts per decade and an On/Off current ratio of ~106. Simulations show an effective channel length of ~3.9 nm in the Off state and ~1 nm in the On state.