Sol-gel growth of vanadium dioxide

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5577760

Speck, K R

This thesis examines the chemical reactivity of vanadium (IV) tetrakis(t-butoxide) as a precursor for the sol-gel synthesis of vanadium dioxide. Hydrolysis and condensation of the alkoxide was studied by FTIR spectroscopy. Chemical modification of the vanadium tetraalkoxide by alcohol interchange was studied using {sup 51}V NMR and FTIR. Vanadium dioxide thin films and powders were made from vanadium tetrakis(t-butoxide) by standard sol-gel techniques. Post-deposition heating under nitrogen was necessary to transform amorphous gels into vanadium dioxide. Crystallization of films and powders was studied by FTIR, DSC, TGA, and XRD. Gel-derived vanadium dioxide films undergo a reversible semiconductor-to-metal phase transition near 68C, exhibiting characteristic resistive and spectral changes. The electrical resistance decreased by two to three orders of magnitude and the infrared transmission sharply dropped as the material was cycled through this thermally induced phase transition. The sol-gel method was also used to make doped vanadium dioxide films. Films were doped with tungsten and molybdenum ions to effectively lower the temperature at which the transition occurs.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (United States)
• OSTI ID: 5577760
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKOXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTALLIZATION
DECOMPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FILMS
HYDROLYSIS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LYSIS
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POWDERS
RESONANCE
SOL-GEL PROCESS
SOLVOLYSIS
SPECTROSCOPY
STABLE ISOTOPES
SYNTHESIS
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
VANADIUM 51
VANADIUM COMPOUNDS
VANADIUM ISOTOPES
VANADIUM OXIDES