Niobium and rhenium doping in MoSe2 monolayer during molecular beam epitaxy: Shallow dopants and defect proliferation

Monolayer (ML) transition-metal dichalcogenides (TMDs) have attracted a lot of research interest in recent years due to their many interesting properties as well application promises. Depending on the specific combinations metals (e.g., Mo and W) with chalcogen elements S, Se, Te), binary TMDs exhibit wide spectrum physical characteristics, e.g., from metal semiconductor and/or superconductor. Extension ternary compounds alloys may offer even wider variations are thus both fundamental practical points view. In this work, we substitute for niobium (Nb) rhenium (Re) ML MoSe2 during molecular-beam epitaxy probe effects structural electrical properties. We find that low-concentration Nb Re ML-MoSe2 shallow dopants, being an electron donor acceptor, respectively. By changing Nb(Re)/Mo flux ratios, can effectively tune Fermi level by varying or hole concentrations MoSe2. On other hand, found cause mirror-twin domain boundary defects proliferate