Abstract
The growing interest in two-dimensional (2D) materials is driven by their remarkable physical properties and potential applications in next-generation electronic and optoelectronic devices. However, developing effective doping strategies for atomically thin layers remains a significant challenge. This study aims to investigate the effects of Cr, Ta, and Mn doping at a concentration of 22.22% on the structural, electronic, and optical properties of monolayer molybdenum disulfide ( \(\hbox{MoS}_{{2}}\) ), using density functional theory (DFT) with van der Waals corrections. DFT calculations are employed to assess the changes in bond lengths, bulk modulus, and volume as well as the bandgap and electronic structure of doped MoS2. Optical properties such as dielectric constants, absorption edges, and plasmon peaks are also examined. The results show that doping does not affect the structural integrity of \(\hbox {MoS}_{{2}}\) . Cr–S and Mn–S bond lengths are found to be 2.41 Å and 2.42 Å, respectively, while the Ta–S bond length increases to 3.22 Å. Cr-doped \(\hbox {MoS}_{{2}}\) retains a similar bulk modulus (45.50 GPa) and volume (113.87 Å \({ ^3}\) ) compared to the undoped system. Cr and Mn doping preserve the direct-bandgap nature, reducing it to 1.60 eV and 1.35 eV, respectively, while Ta induces an indirect bandgap of 1.72 eV. The doped systems exhibit type II band alignment, with strong d-orbital hybridization around 2.0 eV to 2.5 eV, which facilitates enhanced charge separation. Optically, the in-plane dielectric constants decrease, and the absorption edges shift to higher energies for all doped systems, with Cr, Ta, and Mn shifting to 2.78 eV, 2.94 eV, and 3.05 eV, respectively. Additionally, plasmon peaks in the electron energy loss spectra are tunable, with shifts to 6.35 eV (Cr), 12.69 eV (Ta), and 6.42 eV (Mn). These findings underscore the significant role of transition metal dopants in modifying the structural, electronic, and optical properties of \(\hbox {MoS}_{{2}}\) , making it a promising material for photodetection applications.
Graphical Abstract
