Room-temperature ferromagnetism in Co doped MoS2 sheets.

Via the hydrothermal method, we synthesized MoS2 nanosheets with varying Co dopant concentrations of 0%, 3%, 7%, using cobaltous acetate as a promoter, and marked as A, B, and C, respectively. We found that the thickness and flatness of the nanosheets increased with the increase of the Co dopant concentrations. Meanwhile, the BET surface area of samples (A, B, and C) decreased with the increase of the Co dopant concentrations. Optical absorption spectroscopy showed that, compared to sample A, the A1 and B1 excitons of samples B and C were 10 and 23 meV redshifted, respectively. Then, we performed magnetization measurement to investigate the effect of Co-doping; the unique result implied that the values of the magnetic moment decreased with the increase of the Co dopant concentrations. We performed DFT computations to address the above magnetic result. The computational result indicated that the value of the magnetic moment decreased with the increase of the Co dopant concentrations, which is in agreement with the results of the experiments described above.