How can I calculate the band gap theoretically and experimentally?
How many methode to calculate band gap experimentally?
I know from Tauc equation you can calculate experimentally by absorbance spectra(UV) but what about α since I have a solution
can we make α=Concentration / Absorbance
Dear Firas,
You can calculate the band gap through the optical measurements. It can be done from analysis of optical absorption or reflection spectra. The first is more convenient for you, since you have a solution. For this, it is not necessary to know the absolute value of the absorption coefficient (alpha), since the optical density data will be sufficient (in many spectrometers the absorption spectra are measured in optical density coordinates).
You can use the Tauc expression: (D*hv)^n=(hv-Eg)
where D is the optical density, hv is the photon energy, Eg is the band gap, n is an exponent, which depends on type of interband transitions (1/2 for indirect transitions and 2 for direct).
After you plot a dependence of function (D*hv)^n (Y-axis) on hv (X-axis), you should see the linear region. The point of intersection this region with the X-axis corresponds to the band gap value.
Good luck
Regards, Yulia
Dear Sir. Concerning your issue about the calculation the band gap theoretically and experimentally . Band gaps of II-VI semiconductors, calculated by the full potential linearized augmented plane wave (FP-LAPW) method with the modified Becke-Johnson (mBJ) potential. The accuracy of the calculated results is assessed by comparing them with the experimentally measured values. After careful analysis of the results presented in this paper, we found that the mBJ potential is very efficient in the predication of the bandgaps of II-VI semiconductors. It is also revealed that the effectiveness of mBJ is based on the proper treatment of the d-orbitals in the highly correlated electron system. I think the following below links may help you in your analysis:
https://arxiv.org/ftp/arxiv/papers/1201/1201.0870.pdf
https://pdfs.semanticscholar.org/bed5/658d0894ec95bbd56283d1c15403327c0d27.pdf https://aip.scitation.org/doi/abs/10.1063/1.4904740?ver=pdfcov&journalCode=jap
Thanks
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