A raman spectroscopic study of MoS 2 and MoO 3: Applications to tribological systems

Bret C. Windom, W. G. Sawyer, David W. Hahn

Research output: Contribution to journalArticlepeer-review

570 Scopus citations


Molybdenum disulfide (MoS 2) and molybdenum trioxide are investigated using Raman spectroscopy with emphasis on the application to tribological systems. The Raman vibrational modes were investigated for excitation wavelengths at 632.8 and 488 nm using both micro-crystalline MoS 2 powder and natural MoS 2 crystals. Differences are noted in the Raman spectra for these two different wavelengths, which are attributed to resonance effects due to overlap of the 632.8 nm source with electronic absorption bands. In addition, significant laser intensity effects are found that result in laser-induced transformation of MoS 2 to MoO 3. Finally, the transformation to molybdenum trioxide is explored as a function of temperature and atmosphere, revealing an apparent transformation at 375 K in the presence of oxygen. Overall, Raman spectroscopy is an useful tool for tribological study of MoS 2 coatings, including the role of molybdenum trioxide transformations, although careful attention must be given to the laser excitation parameters (both wavelength and intensity) when interpreting Raman spectra.

Original languageEnglish (US)
Pages (from-to)301-310
Number of pages10
JournalTribology Letters
Issue number3
StatePublished - Jun 2011
Externally publishedYes


  • Molybdenum disulfide
  • Oxidation resistance
  • Raman spectroscopy

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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