Temperature dependences of the optical properties and the phase composition of vanadium dioxide films obtained by chemical vapor deposition

Resumo

By low pressure chemical vapor deposition single-phase vanadium dioxide films containing monoclinic phase M1from vanadyl acetylacetonate vapor are obtained on monocrystalline silicon Si(100) substrates. Changes in the phase composition of the films on heating to 90 °C are studied by X-ray diffraction. It is found that in the temperature range 60-70 °C the monoclinic phase passes into tetragonal R. At higher temperatures only the tetragonal phase is observed. By reflection spectrophotometry and ellipsometry the temperature dependences of the optical properties of the films exhibiting hysteresis are determined. At wavelengths less than 600 nm the reflection spectra are almost insensitive to temperature variation. After the linear normalization the reflection and extinction coefficients are well consistent with changes in the phase composition.