6533b7d8fe1ef96bd126a369

RESEARCH PRODUCT

Superficial oxidation of molybdenum at high pressure and low temperature: RHEED and AES analyses of the molybdenum oxide formation

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Abstract Numerous studies relate to the interaction of the molybdenum surface with oxygen at low pressure and high temperature. They give results about oxygen chemisorption, surface facetting and the epitaxial formation of MoO 2 crystallites. This work deals with the interaction of Mo(100), Mo(110) and Mo(111) surfaces with oxygen at high pressure (10 4 Pa) and low temperature (620–820 K). RHEED and AES analyses results prove that, in these oxidation conditions: MoO 2 and non-stoichiometric molybdenum oxide such as Mo 4 O 11 are not evidenced in any of the molybdenum oxidation steps. The MoO 3 phase nucleates directly from any Mo surface. The structure and orientation of MoO 3 nuclei are characterized in relation with the parent molybdenum surface. Some MoO 3 nucleation and growth mechanisms are proposed, involving the specific properties of the MoO 3 phase and the structure of molybdenum surfaces.