Solution-Processable Fe-Doped SnSe2 Flakes with Tunable Morphology and Robust Near-Room-Temperature Ferromagnetism

Abstract

SnSe2 has emerges as a promising host for van der Waals (vdW) magnetic semiconductors, yet the realization of robust near-room-temperature ferromagnetism via scalable solution-based synthesis remains a significant challenge. Here, we report low-cost polymer-assisted deposition (PAD) of Fe-doped SnSe 2 flakes exhibiting tunable morphology and strong ferromagnetic ordering up to ~300 K.Undoped SnSe2 exhibits distinctive snowflake-like fractal architectures consistent with diffusion-limited aggregation, which gradually evolves toward compact platelets upon Fe incorporation, revealing a direct correlation between dopant level and morphological control. Magnetic characterization reveals all Fe-doped samples are ferromagnetic, with the 5% Fe composition delivering the highest saturation magnetization and Curie temperature of about 300 K. Comprehensive spectroscopic and magnetic analyses reveal that the observed ferromagnetism arises from a hole-mediated exchange interaction, in which high-spin Fe 2+ ions substituting for Sn 4+ sites simultaneously provide localized magnetic moments and holes. This work establishes PAD as a versatile scalable platform for high-Curie-temperature vdW magnets and highlights the critical interplay of morphology, defects, and doping in tailoring spin functionality in layered semiconductors for next-generation spintronics.