Electron doping induced semiconductor to metal transitions in ZrSe2 layers via copper atomic intercalation

Atomic intercalation in two-dimensional (2D) layered materials can be used to engineer the electronic structure at the atomic scale and generate tuneable physical and chemical properties which are quite distinct in comparison with the pristine material. Among them, electron-doped engineering induced by intercalation is an efficient route to modulate electronic states in 2D layers. Herein, we demonstrate a semiconducting to metallic phase transition in zirconium diselenide (ZrSe2) single crystals via controllable incorporation of copper (Cu) atoms. Our angle resolved photoemission spectroscopy (ARPES) measurements and first-principles density functional theory (DFT) calculations clearly revealed the emergence of conduction band dispersion at the M/L point of the Brillouin zone due to Cu-induced electron doping in ZrSe2 interlayers. Moreover, electrical measurements in ZrSe2 revealed semiconducting behavior, while the Cu-intercalated ZrSe2 exhibited a linear current-voltage curve with metallic character. The atomic intercalation approach may have high potential for realizing transparent electron-doping systems for many specific 2D-based nanoelectronic applications.