Ultrahigh vacuum high resolution transmission electron microscopy of sputter-deposited MoS2 thin films

G. Jayaram*, N. Doraiswamy, L. D. Marks, M. R. Hilton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

High resolution electron microscopy has been used to characterize the structure of sputter-deposited MoS2 coatings under both conventional and ultrahigh vacuum (UHV) conditions. As deposited, the films have a mixture of short-range ordered basal-plane and edge-plane oriented grains near the film substrate interface; structural changes were characterized in a UHV transmission electron microscope as a function of two processing variables: temperature and Au deposition. Annealing in an oxygen environment was also carried out to assess chemical stability. During thermal annealing in UHV and in oxygen, substantial long-range ordering of the basal islands followed by grain growth was observed. Inhomogeneous oxidation resulting in the formation of MoO3 in the initial stages followed by grain growth, yielding the final morphology of a mixture of MoO3 crystallites of 5-50 nm size was seen on annealing in an oxidizing atmosphere. Au nucleation and growth on both thermally annealed and as-deposited films were seen to follow the Volmer-Weber mode, i.e. three-dimensional islands; these islands were also seen to be highly textured. Also, in comparison with carbon and SiO substrates, Au demonstrated higher stability on MoS2 to electron beam fluxes, suggesting higher bonding strengths to the substrate. These experiments demonstrated the paramount need for UHV conditions during both deposition and characterization to avoid uncertain contamination artifacts.

Original languageEnglish (US)
Pages (from-to)439-445
Number of pages7
JournalSurface and Coatings Technology
Volume68-69
Issue numberC
DOIs
StatePublished - Dec 1994

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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