Homogeneous dual-gate MoS₂ field-effect transistors integrated by atomic layer deposition-based film synthesis

Various synthetic approaches have been proposed and studied to grow high-quality two-dimensional (2D) transition metal dichalcogenides (TMDCs) thin films. However, most of current methods suffer from intrinsic material defects or technical limitations. Here, in this paper, large-area few-layer MoS₂ thin films have been prepared on SiO₂/Si substrate through sulfurizing pre-deposited MoO₃ film by atomic layer deposition (ALD). Good film uniformity, crystallinity and stoichiometry have been successfully achieved. The film thickness can be precisely controlled by adjusting the ALD cycle numbers during MoO₃ deposition. Field-effect transistor (FET) arrays have been further fabricated based on the large-area MoS₂ film. Both back-gate and top-gate geometries have been applied and have shown excellent reproducibility in electrical performance with average electron mobility of 1.71 cm² V⁻¹ s⁻¹ and 0.31 cm² V⁻¹ s⁻¹ for the back-gate and top-gate FETs, respectively. Our results have enabled a promising pathway with such thickness-controlled TMD film and homogeneous FET devices towards future low-dimensional nanoelectronics applications.