Two-dimensional semiconducting LuCT (T = F, OH) MXene with low work function and high carrier mobility.

As a new family of two-dimensional materials, MXenes have attracted increasing attention in recent years due to their widespread potential applications. In contrast to early transition metals in convention, here we expand the M element of MXene to the rare earth element lutetium. Based on the first-principles density functional calculations, the bare lutetium-based carbide MXene LuC is determined to be stabilized in the T-type configuration. Furthermore, both fluorine and hydroxyl terminated configurations are found to be semiconductors, and their band gaps are suitable for use in semiconductors and visible and near-infrared optical devices. The LuC(OH) configuration shows a direct band gap and possesses an ultralow work function of 1.4 eV. Both LuCT (T = F, OH) MXenes exhibit high carrier mobilities. Particularly, the electron mobility of the LuC(OH) MXene is found to be anisotropic at room temperature, with values as high as 95.19 × 10 and 217.1 × 10 cm V·s in the zigzag and armchair directions, respectively, which makes LuC(OH) a promising material for nanodevices. Based on these predicted properties, our work widens the range of MXene materials and their applications in semiconducting devices.