Fig. 2: Static terahertz conductivity (absorption) and ultrafast photoconductivity of semiconducting and metallic MXene samples.

a, Static terahertz conductivity of Nb4C3Tx and Ti3C2Tx MXene thin films. b,c, The fluence-dependent, time-resolved photoconductivity of semiconducting Nb4C3Tx (b) and metallic Ti3C2Tx (c) MXenes thin films, following 1.55 eV photoexcitation at room temperature.