Laser Raman Measurements of Dielectric Coatings as a Function of Temperature

    Published: Jan 1991

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    Single crystal Raman spectra of the anatase phase of titania have been acquired as a simultaneous function of temperature and pressure in a heated diamond anvil cell. Measured data are used to construct frequency contours in P,T space for particular allowed vibrational modes. The magnitude of stress in thin films deposited on various substrates and its temperature evolution have been evaluated from correlations between the P,T frequency maps and measured temperature-dependent mode frequencies exhibited by the films. A simple anharmonic oscillator model has been used to relate the temperature-dependence of the square of the mode frequency to the first order anharmonic contribution to the potential energy from which the thermal expansion coefficient (α) of polycrystalline films may be estimated. The stress dependence of α for bulk titania has been determined from this data and is compared with the predicted response of several stressed titania films.

    Author Information:

    Exarhos, GJ
    Pacific Northwest Laboratory, Richland, WA

    Hess, NJ
    Pacific Northwest Laboratory, Richland, WA

    Ryan, S
    Pacific Northwest Laboratory, Richland, WA

    Committee/Subcommittee: F01.19

    DOI: 10.1520/STP23626S

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