Indium Incorporation into Tungsten Disulfide Monolayers during Chemical Vapor Deposition Growth: Doping and Enhancement of Photoluminescence

Tungsten disulfide (WS₂) monolayers have attracted significant attention due to their remarkable electrical and optoelectronic properties, making them promising candidates for next-generation nanoelectronic and optoelectronic devices. In this study, we employed a multitechnique approach to investigate the effects of indium (In) atom incorporation into WS₂ monolayers during chemical vapor deposition growth. Photoluminescence spectroscopy revealed up to a 4-fold increase in emission intensity. Raman spectroscopy showed that the crystalline structure remained intact despite the incorporation of In atoms. X-ray photoelectron spectroscopy (XPS) confirmed the presence of In atoms bonded to both tungsten (W) and sulfur (S). The observed shifts in peaks corresponding to W⁴⁺ and S^2- oxidation statescharacteristic of WS₂along with the change in the valence band maximum (VBM) position, indicated a Fermi level shift toward the valence band, signifying p-type doping. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to analyze the topography and morphology of the samples. These findings provide a foundation for the controlled synthesis of In-doped WS₂, facilitating targeted optoelectronic applications.