<i>In Situ</i> Atomic Tracking on the Interfacial Etching and Reconfiguration of Cu-ReSe₂ Contact during Thermal Annealing

The Schottky barrier height can be greatly affected by the metal diffusion, reaction, and covalent bonding formation at the contact. Exploring novel methods and revealing the fundamental mechanisms for contact engineering are of vital importance for microelectronic devices. Here, the annealing induced interfacial reactions at Cu-ReSe₂ contact are dynamically revealed from the atomic scale. Accompanied by the diffusion of Se to Cu, ReSe₂ is gradually decomposed to a thin Re interlayer through a "chain-by-chain" manner. Theoretical calculations show that the Cu atoms can facilitate the chemical bond breaking of ReSe₂, significantly lowering the Se diffusion energy barrier toward Cu. The formed Re/ReSe₂ heterostructure presents a metal-like band structure, which underscores the critical role of Cu in altering the interfacial chemistry and promoting carrier transport across the interface. Our results can provide vital insights into the contact properties of ReSe₂ and provide a possible method for fabricating high-performance ReSe₂-based devices.