Spintronic THz emitters based on heterostructures of transition metal and cobalt dichalcogenides obtained by liquid-phase exfoliation

Problem Statement: there is a need to create spintronic terahertz radiation sources that go beyond traditional ferromagnet/heavy metal heterostructures. Two-dimensional transition metal dichalcogenides (TMDs) are promising as an interface for spin-charge conversion, but integrating TMDs obtained by liquid-phase exfoliation into THz emitters remains a technologically and methodologically challenging task. Objective: to fabricate and characterize spintronic THz emitters based on TMD/Co heterostructures obtained by liquid-phase exfoliation, assessing the THz signal amplitude, and evaluate the role of interfacial spin-orbit conversion. Results: spintronic THz emitters were fabricated based on heterostructures of three types of dichalcogenides (WS2, WSe2, MoSe2) synthesized by liquid-phase exfoliation. Morphological analysis (scanning electron microscopy, atomic force microscopy) revealed a high coverage density of TMD crystallites (60–80%) with a characteristic size of 5–10 μm and a height of 20–500 nm. Analysis of the phase characteristics of THz pulses shows that, with integral recording, the dominant generation mechanism is ultrafast laser-induced demagnetization of cobalt. Practical Relevance: this work demonstrates the potential of liquid-phase exfoliation as a method for producing active layers of spintronic THz sources. Replacing expensive heavy metals with two-dimensional semiconductors reduces costs and improves the scalability of the technology.