The effect of thermal treatments up to 1300K on the surface structure of MoS2 was studied using scanning tunnelling microscopy. The surface of MoS2 remained atomically perfect up to 1200K. Above 1300K, a reconstruction of the top layers of MoS2 to Mo2S3 was observed, leading to 1-dimensional atomic double rows on the reconstructed surface. First principles based thermodynamic calculations indicate that the thermodynamically preferred surface was the sulfur rich (001) termination. Low voltage scanning tunnelling microscopy simulations using the ESQC method show good agreement with experimental images.

Surface Reconstruction of MoS2 to Mo2S3. R.K.Tiwari, J.Yang, M.Saeys, C.Joachim: Surface Science, 2008, 602[15], 2628-33