I Need to measure the band position of my semiconductor material. how can I calculate it through different methods? Your detail answer will be highly appreciated.
In solution you can measure the position of HOMO and LUMO which "corresponds" to valence and conduction bands. I used a method implementig ferrocene as standard. You should find the procedure in the publication attached.
Article Efficient two layer LEDs on a polymer blend basis
Thank you dear Andrea Magri. This method can be best employed for organic materials. But in case of semiconductors, i am still not confident to use this.
I used it for small molecule organic semiconductors, e.g. Alq3. It works only in solution, of course with standard CV equipment. By measuring oxidation and reduction peaks you can estimate HOMO-LUMO and therefore the GAP. I do not know the nature of your semiconductors. If they are crystals (and so you have bands), CV in solution might be not the best way as the solubilization breaks the crystals and therefore you have no bands anymore.
I appreciate your effort dear Andrea Magri. Thank you very much for your valuable answer.
Many issues should be examined. A major issue is that both HOMO and LUMO should be in the Voltage stability window of an (low concentration) electrolyte.
Dear Ibrahim,
Many methods, like CV, UPS, UV-Vis, XPS and EIS, have been utilized for the estimation (not the exact value) of the valence band and conduction band as well as the band gap of a semiconductor. Apart from UPS the rest of the methods can not give accurate answer on their own. I would say you need a combination of methods.
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