The band gap of TiO2 nanowires (semiconductor) was measured by UV-Vis spectroscopy using Kubelka-Munk function.
Then how to measure the level of the conduction band or/and valence band edge of TiO2 nanowires?
I want to know the energy level difference between different phases in TiO2 (anatase, rutile and layered titanate).
Thank you
There are several spectroscopic techniques available to evaluate the conduction or valence band edges including XPS and EELS. In our lab, we use electrochemical techniques. Using Mott-Schottky analysis, we determine the flat band potential (that gives the Fermi level), and charge carrier density (ND). The conduction band minimum is shifted from the Fermi level by kT ln(ND/Nc), where Nc = effective density of states in the conduction band based on the solid state physics principles. Several papers are available in this area. One of our paper that may be useful to you is: Journal of The Electrochemical Society, 162 (6) H1-H12 (2015)
Hi,
The easy and widely accepted method is to use the combination of valance band XPS + Mott-Schottky analysis (electrochemistry). Mott-Schottky analysis, will give you the position of band (either VB or CB) depending on the material and XPS will give you the VB. For reference one of our paper is attached (all equations and methods are there). Best wishes
SD
Hi,
You have determined the bandgap of TiO2 nanowires using the Tauc plots derived from the reflection spectroscopy. Now you might need to conduct UPS analysis to obtain the VB edge value. The conduction band edge could be drived by simply adding the VB and bandgap values. Now you have a good estimation of the energy levels in your semiconductor.
Hope that would help you.
All the best,
Ke
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