Improving the Photoelectric Characteristics of MoS₂ Thin Films by Doping Rare Earth Element Erbium

We investigated the surface morphologies, crystal structures, and optical characteristics of rare earth element erbium (Er)-doped MoS₂ (Er: MoS₂) thin films fabricated on Si substrates via chemical vapor deposition (CVD). The surface mopography, crystalline structure, light absorption property, and the photoelectronic characteristics of the Er: MoS₂ films were studied. The results indicate that doping makes the crystallinity of MoS₂ films better than that of the undoped film. Meanwhile, the electron mobility and conductivity of the Er-doped MoS₂ films increase about one order of magnitude, and the current-voltage (I-V) and the photoelectric response characteristics of the Er:MoS₂/Si heterojunction increase significantly. Moreover, Er-doped MoS₂ films exhibit strong light absorption and photoluminescence in the visible light range at room temperature; the intensity is enhanced by about twice that of the undoped film. The results indicate that the doping of MoS₂ with Er can significantly improve the photoelectric characteristics and can be used to fabricate highly efficient luminescence and optoelectronic devices.