Hi, I need to measure the real-time (or temporal intervals) thickness variation of a transparent material from dry to wet/humid conditions, however, I cannot use the following techniques:
- Microscopies such as SEM or TEM are under vacuum, which dry the sample and I cannot obtain measurements in wet conditions;
- Conventional Mitutoyo micrometers compress/smash/damage the surface/stick to the the surface of the thin film;
- AFM is affected by surface roughness changes and water molecules
- Optical microscopies had limitations. Is there any thickness calibration standard?
I'm considering using some UV-Vis reflection measurements but don't know the limitations, for example not much diffusion of this technique Or if is necessary one special tool apparatus in the UV-Vis.
Merci
Ellipsometry is a relatively simple and standard technique for this measurement. A beam of polarized light is reflected from the sample at a convenient oblique angle (so this can be done in situ during thin film deposition). The polarization ellipse of the reflected beam is analyzed. This can be done as a function of angle of incidence and/or wavelength. If both this is Variable Angle Spectroscopic Ellipsometry (VASE). The expected behavior of a dielectric film or stack of dielectric films is readily calculable. So it is not difficult to least squares fit the measurement to a parameterized model of the film stack.
There are any number of commercial units available with automated continuous determination of film thickness and dielectric properties. They can be expensive. But the measurement principle is simple, so an enterprising clever person can put together a poor man’s version particularly for your relatively simple case.
Ultrasonik dalga hızını ölçerek yapılabilir. Bu durum cismin ıslak ve kuru hali için ayrı ayrı yapılır. Deney ultrasonik test cihazı ile yapılabilir.
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