Surface structure modification of ReSe ₂ nanosheets via carbon ion irradiation

The effects of C ion irradiation on multilayer ReSe ₂ flakes are studied by utilizing different kinds of technologies. The domain sizes, thickness, morphologies of the multilayer ReSe ₂ flakes on the Al ₂O ₃ substrates before and after 1.0-MeV C ion irradiation with different fluence rates are studied by atomic force microscope and scanning electron microscopy. The atomic vibrational spectra of multilayer ReSe ₂ flakes are detected by micro-Raman spectra. The redshifts of the Raman modes after 1.0-MeV C ion irradiation are observed from the micro-Raman spectra. The elemental compositions and bonding configurations of the multilayer ReSe ₂ samples before and after irradiation processes are characterized by x-ray photoelectron spectroscopy. The structural properties are also investigated by x-ray diffraction, and it is concluded that after 1.0-MeV C ion irradiation process, multilayer ReSe ₂ samples continue to grow on Al ₂O ₃ substrates, the increase of crystallite size also reveals that the crystallinity is improved with the increase of the layer number after 1.0-MeV C ion irradiation.