Developing a Low-Temperature Pathway for the Synthesis of Two-Dimensional WS2 Nanosheets

Since their discovery in 2004, two-dimensional (2D) materials have attracted great attention due to their unique mechanical, electrical, and chemical properties. However, their integration into devices is limited by the high temperatures required for crystalline growth, which prevents the use of flexible and biocompatible substrates like polymers for biomedical and next-generation electronic devices. This project aims to therefore develop a low-temperature synthesis process for two-dimensional tungsten disulfide (WS₂), a material particularly promising due to its tunable bandgap and biocompatibility. We propose that by first depositing an intermediate tungsten oxide film (WOx) via Hollow Cathode Plasma-Assisted Atomic Layer Deposition (HCP-ALD) and then sulfurizing the film through hydrothermal sulfurization, a maximum temperature below 250 °C can be achieved. Initial trials of depositing WOx films on Si substrates at 150 °C and 200 °C showed a relatively high GPC values of 0.695 Å and 0.888 Å, respectively, and XRD measurements indicate significant (022), (240), and (241) orientations present in grown films. These findings show the possibility and benefits of using HCP-ALD to deposit WOx films at low temperatures and lays the groundwork for further study and optimization of growth parameters and resulting effects.