REAL-SPACE IMAGING OF SINGLE-LAYER MOS2 BY SCANNING TUNNELING MICROSCOPY

Single layers of MoS2 have been studied with a scanning tunneling microscope operating in air. The images obtained from films that were prepared by depositing an aqueous suspension of single-layer MoS2 on a graphite surface show that the unit cell of the single layers corresponds to an approximate 2a0 x a0 superlattice of the hexagonal 2H-MoS2 structure. The unit-cell parameters, in conjunction with previous measurements, imply that the single layers of MoS2 adopt a distorted octahedral structure. The image of dry restacked MoS2 transforms back to the hexagonal MoS2 pattern.