Revealing the anisotropic phonon behaviours of layered SnS by angle/temperature-dependent Raman spectroscopy. Issue 50 (10th November 2022) - Gong, Xiangnan
Abstract : The angle-resolved polarized Raman spectroscopy, combined with electron backscattered diffraction technology to determine the in-plane orientation of SnS crystal. Abstract : Tin sulfide (SnS), a IV–VI group layered compound, has attracted much attention because of its excellent thermoelectric properties along the crystallographic b -axis. However, there are few reports on the identification of its in-plane orientation. We observe a strong anisotropy of the in-plane Raman signal in bulk SnS. With the help of ab initio calculations, the vibrational symmetry of each observed Raman mode in the cleaved (00 l )-plane is consistent with the experimental values. The angle-resolved polarized Raman spectroscopy, combined with electron backscattered diffraction technology, is utilized to systematically investigate the in-plane anisotropy of the phonon response and then determine the in-plane orientation. Furthermore, the temperature-dependent and laser-power-dependent Raman scattering analyses reveal that the adjacent layers in the SnS crystals show a relatively weak van der Waals interaction. These findings could provide much-needed experimental information for future applications related to the anisotropic transport properties of SnS single crystals.