Two-dimensional (2D) van der Waals ferromagnetic materials have attracted intense attention due to their potential impact on both fundamental and applied research studies. Recently, a new 2D ferromagnet CrTe2, prepared by mechanical exfoliation or chemical vapor deposition, has gained interest due to its novel magnetic properties. In this work, high quality CrTe2 epitaxial thin films were prepared on GaAs (111)B substrates using solid source molecular beam epitaxy, with the thickness varying from 35 to 4 monolayers (MLs). The magnetic easy axis of all the films is oriented along the c-axis. A Curie temperature of 205 K is found in the 35 ML CrTe2 film, measured by the temperature-dependent anomalous Hall resistance (RAHE). Importantly, even when the film thickness decreases to 4 MLs, a robust out-of-plane ferromagnetism with a Curie temperature of 191 K has been demonstrated. This finding could pave the way for investigating the fundamental studies in 2D ferromagnetism and has great significance in device applications.

To develop MoSe 2 -based photocatalysts, increasing the catalytic activity of 2H-MoSe 2 is essential. In this work, the electronic and photocatalytic properties of 3d transition metal-doped (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) 2H-MoSe 2 were investigated by first-principles calculations. The results indicate that Sc, Ti, V, Cr, Mn, Fe, and Co atoms tend to substitute the Mo atoms under a Se-rich condition, whereas Ni, Cu, and Zn atoms prefer to occupy the interstitial positions. More importantly, Scand Ti-doped 2H-MoSe 2 can enhance the photocatalytic activity by increasing the oxidizability of photogenerated holes, suppressing the recombination of photogenerated carriers, and increasing the number of catalytic active sites.

In this study, nano-sized fullerene C60 powder was sufficiently mixed with Cu2SnSe3 powder by ball milling method, and the C60/Cu2SnSe3 composites were prepared by spark plasma sintering technology. The fullerene C60 distributed uniformly in the form of clusters, and the average cluster size was less than 1 μm. With increasing C60 content, the electrical conductivity of C60/Cu2SnSe3 composites decreased, while the Seebeck coefficient was enhanced. The thermal conductivity of composites decreased significantly, which resulted from the phonon scattering by the C60 clusters located on the grain boundaries of the Cu2SnSe3 matrix. The highest figure of merit ZT of 0.38 was achieved at 700 K for 0.8% C60/Cu2SnSe3 composite.