Scanning Tunneling Microscope Induced Crystallization of Fullerene-like MoS2

Abstract

Amorphous precursors, like MoS3 (WS3), were shown before to be an ideal precursor for the growth of inorganic fullerene-like material in a rather slow crystallization process which lasts anything from 1 h at 800−900 °C1,2 to a few years at ambient conditions.3,4 Using a few microsecond short electrical pulses from the tip of a scanning tunneling microscope, crystallization of amorphous MoS3 (a-MoS3) nanoparticles, which were electrodeposited on a Au substrate into MoS2 nanocrystallites with a fullerene-like structure (IF-MoS2), is demonstrated. The (outer) shell of each nanocrystallite is complete, which suggests that the reaction extinguishes itself upon completion of the crystallization of the MoS2 layers. A completely different mode of crystallization is observed in the case of continuous a-MoS3 films. Here tiny (2−3 nm thick) 2H-MoS2 platelets are observed after the electrical pulse, suggesting a very rapid dissipation of the thermal energy through the gold substrate, in the continuous domain. Since t...