yes
you must have absorbance and transmittance spectra of your sample.
absorption coefficient (alpha)= 2.303 A/d
A is absorbance and (d) is the thickness of your thin films
you must calculate the reflectance using following equation
alpha=-1/d Ln(T/(1-R)*2)
the extinction coefficient (k) is given by
k= (alpha*landa)/(4Pi)
landa is wavelength and Pi=3.14
then you can find the refractive index(n) using this equation
R=[(n-1)**2 + k**2]/[(n+1)**2 + k**2]
yes
you must have absorbance and transmittance spectra of your sample.
absorption coefficient (alpha)= 2.303 A/d
A is absorbance and (d) is the thickness of your thin films
you must calculate the reflectance using following equation
alpha=-1/d Ln(T/(1-R)*2)
the extinction coefficient (k) is given by
k= (alpha*landa)/(4Pi)
landa is wavelength and Pi=3.14
then you can find the refractive index(n) using this equation
R=[(n-1)**2 + k**2]/[(n+1)**2 + k**2]
Dear Ramezan Sahebi : i have already used the formula what you have mentioned for reflectance but i am getting zero reflectance for all wavelengths (300nm-800nm) that is why i am doubtful.
Dear Aras Kartouzian: for the formula mentioned by you i am getting negative reflectance for 300nm to 380nm wavelength range.
Any suggestion from you in this regard? Thanks for your replies.
you can get it from the transmittance only it depends on the range of the wavelength you have and how of transmission behave vs wavelength, For example if you got maximums and minimums in the transmission spectra you could use Swanpol`s method to find n, thickness and other optical constant, and if there is no peaks you could use one of direct equations that others mentioned before.
Dear Shashikant Sharma
did you have used a UV-Vis spectrometer to measure transmittance and absorption spectra? such instruments measure the transmittance and turn it to absorbance using this formula A= Ln(1/T).. so you cant get the reflectance using that.
i think you must get the transmittance using a UV-Vis spectrometer and the reflectance by another instrument then calculate the absorbance spectra.
Based on the envelope method of the transmittance data we can find the thickness of the film.
papers like envelope method by swanepoel method thin films. u can search.
how can i measure the transmittance (T) using Fresnal equation in Ellipsometer?
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