Surface analysis of two misfit layer compounds — (PbS)1.18(TiS2) and (PbS)1.18(TiS2)2 — by scanning probe microscopies (AFM and STM) and X-ray photoelectron spectroscopy (XPS)

Scanning tunneling microscopy, atomic force microscopy and X-ray photoelectron spectroscopy were used to study the surface of two misfit layer compounds, (PbS)1.18(TiS2) and (PbS)1.18(TiS2)2. For the cleaved compounds, STM and AFM images in air and at room temperature revealed the trigonal symmetry of the transition metal dichalcogenide TiS2-1T. After a few hours of exposure to air, AFM and XPS show that the surfaces are strongly modified, with different features according to the mono or the bilayer misfit compounds considered. Depending on the time exposure to air, these results were interpreted in terms of hydrolysis and oxidation reactions.