Plasma-Driven Selenization for Electrical Property Enhancement in Janus 2D Materials

The recent emergence of Janus 2D materials like SnSSe, derived from SnS₂, reveals unique electrical and optical features, such as asymmetrical electronic structure, enhanced carrier mobility, and tunable bandgap. Previous theoretical studies have discuss the electronic properties of Janus SnSSe, but experimental evidence is limited. This study presents a two-step method for synthesizing Janus SnSSe, involving hydrogen plasma treatment and in situ selenization. Optimized conditions (38 W, 1.5 min, 250 °C) are determined using Raman spectroscopy and AFM analysis. XPS confirmed SnSSe's elemental composition, while KPFM reveals a significant reduction in the work function (from 5.26 down to 5.14 eV) for the first time, indicating asymmetrically induced n-type doping. Finally, field-effect transistors (FETs) derived from SnSSe exhibited significantly enhanced mobility and on-current, as well as n-type doping, compared to SnS₂-based FETs. These findings lay a crucial foundation for developing high-performance 2D electronic and optoelectronic devices.