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 MoS 2 crystals in an atmospheric pressure chemical vapor deposition (APCVD) system. The hydrothermal method is employed to deposit various nanostructures of MoO 3, which serves as primary precursors for MoS 2 growth via the APCVD method. Additionally, hydrothermally grown vanadium(V)-doped MoO 3 was used as a precursor resulting in V-doped MoS 2 crystals. Optical and Raman characterization techniques are employed to evaluate the surface morphology, thickness, and crystalline nature of the deposited pristine and V-doped MoS 2 crystals. Furthermore, the sensing performance of pristine and V-doped MoS 2 is investigated toward 100 ppm of NH 3 exposure at room temperature. The V-doped MoS 2 sensor exhibits an enhanced sensing response (25) compared to the pristine MoS 2 sensor response (15.6). In addition, the fabricated V-doped MoS 2 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 MoS 2 crystals, which holds great promise for future electronic and gas sensing applications.