Hybrid Fabrication and Characterization of Two-Dimensional Vanadium Diselenide Related Materials

Abstract

Two-dimensional (2D) van der Waals (vdW) materials have attracted significant interest for next- generation spintronic, electronic, and energy-storage applications due to their unique layer-dependent properties, including magnetism, charge transport, and mechanical flexibility. Nevertheless, the development of robust and scalable devices remains challenging. Key issues include the air sensitivity of many 2D crystals, difficulties in integrating conventional lithographic methods without contamination, and obstacles in forming uniform, high-quality oxide barriers for tunneling applications. In this work, a “hybrid” fabrication method is introduced that combines confocal laser-induced oxidation with inductively coupled plasma (ICP) etching, providing a mask-free, controllable strategy for surface modification and patterning. Vanadium diselenide (VSe2) is used as a demonstration platform, wherein localized laser irradiation in an oxygen-rich environment generates a vanadium pentoxide (V2O5) layer with adjustable thickness and lateral dimensions. By exploiting differential ICP etch rates for VSe2 and V2 O5, selective removal enables precise device geometries to be defined without the need for polymeric masks or chemical developers. The resulting oxide barrier can serve as an ultrathin insulating layer suitable for tunneling magnetoresistance (TMR) applications, while preserving a cleaner oxide–metal interface to mitigate spin-scattering defects and pinholes. In addition, localized oxidation or doping introduced at the oxide interface can potentially modify magnetic anisotropy, suggesting a route toward perpendicular magnetic anisotropy (PMA) in 2D magnets that typically exhibit in-plane magnetization. Beyond VSe2, this approach is compatible with other 2D magnets and transition metal dichalcogenides (e.g., MoS2, WSe2, MnBi2Te4), facilitating the design of multi-barrier tunnel junctions, lateral heterostructures, and integrated energy-storage architectures without conventional mask alignments. The method’s scalability is supported by the widespread availability of industrial laser scanning platforms and standard ICP tools. Overall, the hybrid laser– plasma fabrication presented here addresses critical barriers to integrating 2D materials in spintronic devices and lays the groundwork for the creation of novel magnetic and electronic architectures.