I prepared a transparent conducting materials, it is a highly absorbing light nearly at 380 nm, so it is difficult to evaluate its band gap. Is there another technique available to find out the band gap?
XPS can also measure the electronic band gap if you scan the valence band area.
@Vladimir: this is problematic, since you don't know a priori, where the chemical potential hooks up. A combination of photoemission and inverse photoemission might do the job, though.
@ Firoz: If you have a large band gap, then you will need some tool providing the gap energy in order to probe it. In principle you should be able to expand your UV-VIS capability to beyond 380 nm, it could go as far as 190mm, in principle (e.g. by flooding the spectrometer with pure nitrogen gas instead of air. Of course you may still be limited by other parts and/or the detector).
Ellipsometry and photoluminescence are alternative optical techniques. While they deliver complementary and valuable information, using them still means to have corresponding light sources and spectrometers covering the energy range up to the band gap energy.
Other techniques will get you in the realm of surface science which is demanding in terms of sample characterization, quality and treatment. techniques to mention would be the combination of PES and IPES as mentioned by Vladimir and myself above, or inelastic electron scattering (EELS).
the latter might also be doable in a TEM equipped with an EELS spectrometer. this might be one of the more accessible routes. hovwever, it will only work on very thin chunks of material.
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