Synergistic Approach for Controlled Doping in a MoS2 Monolayer for Enhanced NH3 Sensing

Transition metal dichalcogenide (TMD)-based two-dimensional (2D) materials have attracted significant interest due to their unique electronic and optical properties. In this study, we have proposed a facile two-stage synergistic route for the deposition and controlled doping of MoS2 crystals in an atmospheric pressure chemical vapor deposition (APCVD) system. The hydrothermal method is employed to deposit various nanostructures of MoO3, which serves as primary precursors for MoS2 growth via the APCVD method. Additionally, hydrothermally grown vanadium(V)-doped MoO3 was used as a precursor resulting in V-doped MoS2 crystals. Optical and Raman characterization techniques are employed to evaluate the surface morphology, thickness, and crystalline nature of the deposited pristine and V-doped MoS2 crystals. Furthermore, the sensing performance of pristine and V-doped MoS2 is investigated toward 100 ppm of NH3 exposure at room temperature. The V-doped MoS2 sensor exhibits an enhanced sensing response (25) compared to the pristine MoS2 sensor response (15.6). In addition, the fabricated V-doped MoS2 sensor exhibits a limit of detection (LoD) and a limit of quantification (LoQ) of 80 and 260 ppb, respectively. Our findings suggest an effective and simple route for the uniform and controlled doping of monolayer MoS2 crystals, which holds great promise for future electronic and gas sensing applications.