HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPY OF HEXAGONAL AND RHOMBOHEDRAL MOLYBDENUM-DISULFIDE CRYSTALS

Natural (molybdenite) and synthesized molybdenum disulfide crystals ha ve been studied by high-resolution transmission electron microscopy. T he image simulation demonstrates that the 0001! and 0110BAR! HRTEM i mages of hexagonal and rhombohedral MoS2 crystals hardly disclose thei r stacking sequences, and that the 2110BAR! images can distinguish th e Mo and S columns along the incident electron beam and enable one to determine not only the crystal structure but also the fault structure. Observed 0001! images of cleaved molybdenite and synthesized MoS2 cr ystals, however, reveal the strain field around partial dislocations l imiting an extended dislocation. A cross-sectional image of a single m olecular (S-Mo-S) layer cleaved from molybdenite has been observed. Sy nthesized MoS, flakes which were prepared by grinding have been found to be rhombohedral crystals containing many stacking faults caused by glides between S/S layers.