There is a good discussion about that in chapter 3 in book Optical Processes in Semiconductors, J. I. Pankove.
you can from calculate relationship between photon energy and (alpha *h*v)^n, where n is 2 or 0.5 . That depend on type of band gap if direct or un-direct. Then plot this relation and take band gap value from the intercept of (αhν) versus hν curve plotted.
Have a look at this publication
"Mimicking Natural Fibrous Structures of Opals by Means of a Microemulsion-Mediated Hydrothermal Method" Langmuir 2011, 27, 8905–8912
You can get it from my publication list in Research Gate
Considering the curve that plots the value of (hν - (hνF(R∞))2
The value associated with the point of intersection of the line tangent to the plotted curve (inflection point with the horizontal axis (hν axis becomes the band gap Eg value. The Eg values obtained using Shimadzu's UVProbe software gives the value of Eg and the spectra corresponding to UV or Visible light.
Hi, a simple practical way to analyse data via Tauc gaps is shown in the following paper.
https://www.researchgate.net/publication/224550268_Optical_properties_of_amorphous_Cdiamond_thin_films?ev=prf_pub
How the data can then be used to get more data such as the Urbach tail widths and relate this to refractive index and build a density of states can be seen in the following:
https://www.researchgate.net/publication/224883049_Nitrogen_modification_of_hydrogenated_amorphous_carbon_films?ev=prf_pub
https://www.researchgate.net/publication/224882810_Probing_the_band_structure_of_hydrogen-free_amorphous_carbon_and_the_effect_of_nitrogen_incorporation?ev=auth_pub
Good luck with the analysis.
Article Optical properties of amorphous C/diamond thin films
Article Nitrogen modification of hydrogenated amorphous carbon films
Article Probing the band structure of hydrogen-free amorphous carbon...
Sorry, if i am adding on to the question, but how does one determine "alpha" from the absorption spectrum assuming one doesnt have access to a DRS setup and is using a regular UV-spec? I understand from the explanations provided that we can plot hv vs "alpha"hv, but i was wondering how does one go about finding alpha for a solution using an absorption spectrum
Thanks and sorry if i railroaded the discussion :)
Here you can find good explanation and band gap calculator,
http://www.instanano.com/characterization/theoretical/uv-vis-spectroscopy-band-gap-calculation/
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