Extended Data Fig. 7: Comparison of metallic Co_0.5MoS₂ and semiconducting Co_0.16MoS₂ with lower Co concentration.

a,b, XPS spectra of Mo 3d in Co_0.5MoS₂ and Co_0.16MoS₂, demonstrating partial 1T-phase transition in Co_1/2MoS₂ (a) and preservation of 2H-phase in Co_0.16MoS₂ (b). The Co concentration was controlled by reducing the initial Li-intercalation concentration. c,d, PL spectra of Co_0.5MoS₂ and Co_0.16MoS₂ nanoflakes before (black) and after (red) Li-intercalation/cation-exchange process. In comparison with notable PL degradation (due to 1T-phase transition) in Co_0.5MoS₂, little PL degradation is observed in Co_0.16MoS₂, confirming the preservation of 2H-semiconducting phase. Inset of d shows the OM image of Co_0.16MoS₂ flake and corresponding PL intensity mapping at 680 nm. e,f, Corresponding M-H loops of Co_0.5MoS₂ and Co_0.16MoS₂ at 300 K, respectively. The S-shaped M-H curve confirms ferromagnetic ordering in Co_0.16MoS₂ at 300 K.