Two-dimensional semiconducting Lu₂CT₂ (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 Lu₂C 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 Lu₂C(OH)₂ configuration shows a direct band gap and possesses an ultralow work function of 1.4 eV. Both Lu₂CT₂ (T = F, OH) MXenes exhibit high carrier mobilities. Particularly, the electron mobility of the Lu₂C(OH)₂ MXene is found to be anisotropic at room temperature, with values as high as 95.19 × 10³ and 217.1 × 10³ cm² V^-1·s^-1 in the zigzag and armchair directions, respectively, which makes Lu₂C(OH)₂ a promising material for nanodevices. Based on these predicted properties, our work widens the range of MXene materials and their applications in semiconducting devices.