LAUSR

Abstract Transition metal dichalcogenides generally have three atomic layers forming a buckled honeycomb structure as a covalent sheet. The van der Waals force is the key interaction between these sheets. In our work, we have fabricated a single layered copper selenide structure by employing molecular beam epitaxy method. The selenium and copper atoms form a Moire pattern with respect to the substrate Cu(111). Combined with density functional theory calculation, the narrow band gap of these structures is investigated in detail.