Ti2CO2/Ti2CF2 van der Waals heterostructure with robust Schottky barriers under electric fields

Left. Top view and side view of the optimized lattice structure of Ti2CO2/Ti2CF2. The parallelogram with dashed line denotes the 2D unit cell. Right. The Schottky barrier height of the Ti2CO2/Ti2CF2 heterostructure as a function of the external electric field. [Display omitted] •A novel Ti2CO2/Ti2CF2 van der Waals heterostructure is designed and the band structures of each layer are well preserved.•The Schottky barrier height of the Ti2CO2/Ti2CF2 heterostructure is robust under external electric field.•The robust Schottky barrier opens the possibility of MXenes device designs for nanoelectronics. Transition metal carbides, nitrides and carbonitrides (MXenes) are considered as multifunctional materials due to their various elemental composition possibilities, surface functional tunability, various magnetic orders, and large spin–orbit coupling. Herein, a novel Ti2CO2/Ti2CF2 heterostructure is designed and its electronic and interfacial properties are investigated based on first-principles calculations. Our results reveal that the band structures of Ti2CO2 and Ti2CF2 layers are well preserved in the heterostructure due to the van der Waals interaction between the two layers, and a n-type Schottky contact forms due to the band bending at the interface. The most striking and much novel property is that the Schottky barrier height is nearly independent of the intensity of external electric field which is kept along the direction perpendicular to the Ti2CO2 or Ti2CF2 plane. The result denotes that a Fermi level pinning behavior occurs upon varying the intensity of electric field, which can change the doping concentration of electrons in the Ti2CO2 layer. This robust Schottky barrier opens the possibility of MXenes device designs for nanoelectronics.