Síntese e caracterização de filmes finos e nanoestruturas de SnS

Abstract

In this work, we studied the synthesis and properties of SnS films and nanostructures obtained by a simple method of deposition by vapor phase under controlled pressure. First, we treated the commercial SnS powder thermally to eliminate undesired phases, SnS2 and Sn2S3. To demonstrate the purification of the powder we compared the X-ray diffraction patterns measured for the untreated powder, treated and the reference. Subsequently, we synthesized samples with different temperature configurations and obtained SnS structures with different morphologies. We observed that the growth of the isolated crystals is favored by a small temperature gradient and the films by a large temperature gradient between the sublimation and deposition regions of the deposition chamber, and the two morphological types can grow in the same sample. We also synthesized isolated grains with atypical semicircular shapes that are generally thinner than orthorhombic crystals. We carried out studies on the crystallographic shape and orientation of orthorhombic crystals isolated from the optical microscopy, scanning electron microscopy (SEM) and surface energies of the crystalline planes of the SnS. We used Raman spectroscopy to identify the phase of the synthesized samples. In addition, the polarized Raman spectroscopy technique helped us confirm the crystallographic orientation of the isolated crystals.