Tuning Electrical and Optical Properties of MoSe₂ Transistors via Elemental Doping

Controlled doping of transition-metal dichalcogenide (TMDC)-layered materials is of great importance for practical device application. Doping of TMDCs and tuning of the bandgap properties remain challenging owing to the difficulty of breaking covalent bonds. In this work, the doping of V, Fe, and Nb atoms into MoSe₂ is successfully synthesized using the chemical vapor transport method. By the absorption of V or Nb dopants, the intrinsic n-type MoSe₂ is tuned to be of p type. A p-n diode based on a homojunction is fabricated by stacking the n- and p-type MoSe₂ vertically. The photoresponse range of intrinsic MoSe₂ is only up to 785 nm. However, the photodetector based on the doped MoSe₂ flake with V, Fe, and Nb can be used up to the near-infrared (1550 nm) region at room temperature. Furthermore, the photoresponse wavelength of a V-doped MoSe₂ could reach up to 10 µm. The results indicate that the elemental doping methods could enrich the electrical and optical application prospects of MoSe₂.