Dear colleagues.....
what is the correct way to calculate the Eg of any semiconductor material, is it the Tauc plot or the cut off wavelength from the uv-visible spectrum, which one is more reliable
thanks
I agree with mr. Gustavo of the Tauc plot to determine the band gap energy of semiconductors may lead to erroneous estimates. Particularly large errors can be associated with characterization of modified semiconductors showing a significant absorption of sub-band gap energy photons
Tauc plot is the authentic way for the calculating the bandgap of any material. There is possibility in error in cut off wavelength from UV-Vis spectra. So for scientific papers or any article Tauc plot is only acceptable.
Tauc plot is the best method, but it depends on how you use it.
You can perform a calculation using the Beer-Lambert law and a transmittance spectrum, considering concentration = 1. However, you have a lot of errors in this measurement.
Kubelka-Munk formula can be used in Diffuse Reflectance Spectrum (DRS), proposing a reliable approximation of the absorption coefficient, and applying the Tauc method.
If you are measuring in thin films, you can perform SE (Spectroscopy ellipsometry) which depends on a mathematical model but gives very reliable information.
Best regards,
GG.
Dear Huda
Measure the reflection (diffusion- for roughness surface) or (specular for mirror surface) --- and use Kubelka-Munk theory to determine Eg .
this method is more accurate because its work on surface only, and its the only way to measure Eg for sample prepared on dark substrate .
Regards
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