Enhanced Thickness Uniformity of MoS₂ Thin Films on SiO₂/Si Substrates via Substrate Pre-Treatment with Oxygen Plasma

We report the enhanced thickness uniformity of chemical-vapor-deposited MoS₂ thin films on SiO₂ substrates through substrate pre-treatment with O₂ plasma. Contact angle measurements indicated that the SiO₂ surface became more hydrophilic with an increase in surface energy after O₂ plasma pre-treatment. Analysis through Raman spectra and transmission electron microscopy measurements revealed that the thickness uniformity of MoS₂ thin films improved over a centimeter scale after the O₂ plasma pre-treatment on SiO₂ substrates. Atomic force microscopy analysis further revealed that O₂ plasma pre-treatment on SiO₂ substrates improved the uniformity of surface roughness in the MoS₂ thin films. These results demonstrate that O₂ plasma pre-treatment on SiO₂ substrates is an effective method of enhancing the thickness uniformity of MoS₂ thin films, providing valuable insights for the advancement of large-scale synthesis of MoS₂ and related transition metal dichalcogenides.