Chemical Vapor Deposition Growth of Degenerate p-Type Mo-Doped ReS₂ Films and Their Homojunction

Substitutional doping of transition metal dichalcogenide two-dimensional materials has proven to be effective in tuning their intrinsic properties, such as band gap, transport characteristics, and magnetism. In this study, we realized substitutional doping of monolayer rhenium disulfide (ReS₂) with Mo via chemical vapor deposition. Scanning transmission electron microscopy demonstrated that Mo atoms are successfully doped into ReS₂ by substitutionally replacing Re atoms in the lattice. Electrical measurements revealed the degenerate p-type semiconductor behavior of Mo-doped ReS₂ field effect transistors, in agreement with density functional theory calculations. The p-n diode device based on a doped ReS₂ and ReS₂ homojunction exhibited gate-tunable current rectification behaviors, and the maximum rectification ratio could reach up to 150 at V_d = -2/+2 V. The successful synthesis of p-type ReS₂ in this study could largely promote its application in novel electronic and optoelectronic devices.