Surface reconstruction of MoS2 to Mo2S3

The effect of thermal treatments up to 1300 K on the surface structure of MoS2 was studied using scanning tunneling microscopy. The surface of MoS2 remained atomically perfect up to 1200 K. Above 1300 K, a reconstruction of the top layers of MoS2 to Mo2S3 was observed, leading to one-dimensional atomic double rows on the reconstructed surface. First principles based thermodynamic calculations indicate that the thermodynamically preferred surface is the sulfur rich (0 0 1) termination. Low voltage STM simulations using the ESQC method show good agreement with experimental images.