I. Electron transfer reactions in binuclear model systems. II. Scanning probe microscopy studies of transition metal dichalcogenides materials: Atomic to nanometer scale properties and surface modifications

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:7166570

Kim, Y

Electron transfer has been studied to understand the electronic coupling in model systems consisting of two redox active ruthenium centers separated by rigid aromatic spacers (8 to 20 [angstrom]). Observations in spectroscopy and electrochemistry suggest that the ruthenium centers interact weakly in those models and that aromatic spacers alone are not sufficient to promote strong electronic coupling. Scanning tunneling microscopy and atomic force microscopy have been used to characterize the structural, electronic and tribological properties of solid lubricants. STM and AFM studies of single crystal MoS[sub 2] and cation (Ni) or anion (Se, Te) doped MoS[sub 2] indicate that the microscopic origin of material wear as well as the local structure and electronic properties should be considered to develop further models of friction and wear in metal dichalcogenide materials. AFM study indicates that wear proceeds at defects, and that MoS[sub 2] wears at least five-times more slowly than NbSe[sub 2]. The oxidation processes of MoS[sub 2] have been characterized by AFM, X-ray photoemission spectroscopy. Samples treated at elevated temperatures in oxygen exhibit that defect formation and oxide growth depend on the temperature and oxidation duration, and that the molybdenum trioxides grow with the b-axis perpendicular to the MoS[sub 2] substrate surface. AFM has been used to machine complex patterns and to form free structural objects in thin layers of MoO[sub 3] grown on the surface of MoS[sub 2]. The AFM tip can pattern lines with [le]10 nm resolution and then image the resulting structure without perturbation by controlling the applied load. Distinct MoO[sub 3] structures can also be defined by AFM machining, and these objects can be manipulated on the MoS[sub 2] substrate surface using the AFM tip.

• Research Organization: Harvard Univ., Cambridge, MA (United States)
• OSTI ID: 7166570
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHALCOGENIDES
MICROSCOPY
WEAR
ORGANOMETALLIC COMPOUNDS
ELECTRON TRANSFER
RUTHENIUM COMPLEXES
SOLID LUBRICANTS
CRYSTAL STRUCTURE
DOPED MATERIALS
MOLYBDENUM OXIDES
MOLYBDENUM SULFIDES
SURFACE FINISHING
COMPLEXES
LUBRICANTS
MATERIALS
MOLYBDENUM COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
360606* - Other Materials- Physical Properties- (1992-)
360603 - Materials- Properties