An expanded Tauc absorption equation and its application to detect all energy gaps and transition types in the band diagram of bulk Silicon

Author(s)

Abstract
This work presents an expansion of the Tauc absorption model equation by incorporating into it five proportional factors. The new equation is then solved for the original exponent factor, normally having a value chosen among 0.5, 3/2, 2 and 3, which is related to the optical transition type involved in typical photon absorption processes. Plots of the derived expression along a selected photon energy absorbance range allow, by using a properly adjusted set of the four introduced factors, to detect the energy band gap in the local absorbance range and to confirm the guessed optical absorption type of the material under study. The obtained results are validated by comparing the experimental absorbance data trace against the plot of the expanded absorption equation model and against the energy band diagram, if available, of the material under study. Repeating this process for other segments of the absorbance data provides additional band gaps and absorption types whose nature can be correlated with existing models of energy bands diagrams of the investigated material. The proposed method is applied to bulk Silicon.

Keywords
Photon absorption, Tauc equation, electron transition types, energy band diagram, band gap, Urbach absorption tail.

Cite this paper
Emmanuel Saucedo-Flores, Rogelio Guerrero Gonzalez, An expanded Tauc absorption equation and its application to detect all energy gaps and transition types in the band diagram of bulk Silicon , SCIREA Journal of Physics. Volume 7, Issue 4, August 2022 | PP. 104-113. 10.54647/physics14469

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