Modulating the electronic properties of 2D MoS2 films via the thickness tuning

2D MoS2 is a promising material for electronics and optoelectronics. Currently, the most cost-effective and simple way of its synthesis on large-scale substrates is sulfurization, resulting in nanocrystalline films. These films are very specific objects, which deserve special attention. Making appropriate metallic contacts to nanocrystalline MoS2 is also assumed as another critical challenge. Therefore, in this work we synthesized nanocrystalline MoS2 films via the sulfurization technique and investigated the influence of their thickness on the structural and electrical properties. It was found that the 2.5 nm film contained significantly smaller crystalline grains compared to the 3.5 nm one, but with signs of in-plane orderliness. This film also showed a much higher modulation of ≈2 × 104, which is mainly attributed to the achievement of the very low currents in the Off state, while the 3.5 nm thick MoS2 film essentially retained its conductivity. However, in both cases the FET performance in the On state was solely limited by the contact resistance (Rc). The Arrhenius measurements showed that the effective Schottky barrier height depended on the gate voltage, but generally it was ≈2 times higher for a thinner film. Therefore, the contact engineering technique is not invariant to the film thickness. © 2024 Elsevier Ltd