Optical and electrical tunability in vertically aligned MoS2 thin films prepared by DC sputtering: Role of film thickness

Abstract

Insights into the fundamentals of structure-property relations are one of the most important key parameters, which can be utilized for tailoring material properties such as electrical, and optical for the photonics, optoelectronics, energy storage, and sensing devices. Herein, we report a controlled single-step, large area growth of highly crystalline vertically grown edge exposed MoS2 thin films using DC magnetron sputtering. To understand a correlation between microstructural and material properties, we have prepared MoS2 films of different thicknesses (∼1 nm–440 nm) by varying sputtering deposition times (DT = 1 s–10 min). We have attempted to augment our prevailing understanding of structure-property relations of MoS2 in order to provide large tunability in the optical and electrical properties. Spectroscopic ellipsometry results suggest that the complex refractive index (n and k), dielectric function (Ɛ1 and Ɛ2), and optical bandgap (Eg = 1.35–1.88 eV) are highly dependent on MoS2 film thickness. The MoS2 electrical resistance was observed in the range of ∼15 kΩ–98 MΩ, displaying an inverse relationship with the film thickness.