I have a direct band gap material and an indirect band gap material. If I made a composite of both through physical mixing. Then how can I determine the band gap of such a material as the Tauc plot needs different scheme for both. that is alpha^1/2 for indirect and alpha^2 for direct band gap materials.
Dear Kumail
Perhaps you can perform as follow:
First get the UV-Vis spectrum of the direct band gap material, then,after you prepared your composite get its UV-Vis spectrum as well.from the energy of the peak you obverse in these two spectra you can estimate the band gap of the composite because there is a relationship between absorption band and the band gap.
good luck.
As far as I know - you cannot determine the bandgap of such composite, because it is a junction. You have two bandgaps which may overlap in some region. And when you have to estimate the bandgap using DRS, then better calculate it as for the major component. But in your case, most useful information from DRS measurements will be only the probable change in absorption of the material.
I guess you are talking about alloying. Well, in that case you may try to prepare alloys with various ratios of direct and indirect gap materials and find the crossover concentration.
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