Preparation Of Two-dimensional ReSe₂ Crystal And The Study Of Their Anisotropic Optical Property

With the two dimensional geometry, grapheme-like transition metal dichalcogenides (TMDCs) have attracted great interests because of their excellent physical properties. The energy band of the electron can be changed from indirect band gap to direct band gap when TMDCs becomes 2D structure. This will make a great changes of optical and electrical properties of TMDCs. It known as the "graphene" of the semiconductor. Rhenium diselenide as a member of the family, the study of it is very few. In this paper, the exfoliation method is used to prepare the 2D ReSe2 crystal. Study its anisotropy by peak position and intensity of Raman spectra at different polarization direction. This paper mainly carried out the following work:(1)The preparation of 2D ReSe2 crystal is use exfoliation method. To get rid of the van der Waal’s interaction by repeated tear of bulk material on adhesive tape. Obtain samples of different thickness. Finally, obtain thin layer ReSe2 samples by contrast screening of optical microscope. Then use atomic force microscope to measure the thickness of the sample and know the number of layers of the samples.(2) We measured the material by polarized Raman spectra at different direction, study the anisotropy of ReSe2 samples. For the same layers, study the variation of the Raman peak position and intensity at different polarized direction. Make the intensity of three characteristic peaks to the periodic intensity distribution figure and fit it. Show the variation of the intensity of material.(3)Compare the 3 layer, the 6 layer and the bulk material of the polarized Raman spectra. Study the variation of the relative position of the symmetrical axes of 8 figure of the three characteristic peaks. Study the variation of the maximum intensity of the three characteristic peaks. Study the variation of the same Raman peak intensity of different layers.