Dissertação de Mestrado #605 – Geovani Carvalho de Resende – 09/08/2018

The experimental isolation of graphene by Novoselov and Geim in 2004 opened a horizon in researches of bidimensional materials. These materials present a wide set of desirable physical properties for applications in electronic, optoecletronic, spintronic devices and others. Therefore, the transition metal dichalcogenides (TMDs) form a special class of materials, given the richness of the physical properties of their members, which vary from insulators to superconductors. Rhenium diselenide (ReSe$_{2}$) is a promising semiconductor TMD for electronic and optoelectronic applications, not only because of its band gap in infrared, but also because of its anisotropic properties that emerged from its low symmetry. Since ReSe$_{2}$ is one of the least known TMDs and its anisotropic properties need to be thoroughly understood for future technological applications, this work aims a better understanding of this material, analyzing its vibrational behaviour through Polarized Raman Spec!
troscopy. Then, the angular dependence of the Raman scattering is analyzed by the macroscopic theory of Raman scattering. Moreover, it is necessary to take into account the effect of the phase difference between independent Raman tensor elements to explain the experimental results obtained for most of the vibrational modes predicted by group theory.