I used UV-Vis/NIR spectrophotometer to extract the measurements of refractive index %R corresponding with wavelengths in the range of 190-1100 nm of TiO2 thin film deposited on FTO glass substrate. The TiO2 material is known for its high refractive index and strong absorption in UV-Vis light region according to its phase, XRD shows that my samples was Anatase phase.
I aim to find the optical properties of this thin film including absorbance, band gap, refraction. For refractive index data, I used Jasco V-770 UV-Vis/NIR spectrophotometer (I stick the thin films inside this device and make sure that it cover the source of light) then using OriginLab I plot the attach graph. My questions are:
- Is it possible to determine the refractive index of this thin film from the graph? maybe the highest peak?
- I know that there’s no refractive index in thousands, so why the graph show that y-axes (refractive index) expands from -2900 to 2900? Can anyone explain what that’s mean?
The thickness of TiO2 film is 1.7μm-2.3μm roughly, but I’m not sure, because I used Swanepoel method to estimate it (based on the obtained refractive index measurments and obtained transmittance).
Swanepoel equation: d=(λ_1 λ_2)/(2(λ_1 n_2-λ_2 n_1)) where, n_1 and n_2 are the refractive index at two adjacent interference fringes (maxima or minima) of thin film transmission, at wavelengths λ_1 and λ_2
Here is the data extracting from UV-Vis spectrophotometer: https://docs.google.com/spreadsheets/d/e/2PACX-1vScyJ0NIye6Bpx6o6rqmIVkaaJvc77Cax7EzN2sI4dEw4lKRC5yokxfdoEVdhtyiD-lcGxjN_9mVxck/pubhtml