Can anyone also suggest some info for how to use UPS ( Ultraviolet photoelectron spectroscopy ) for the band gap measurements
I think for very good UPS measurements you would need a very clean surface and part of the art is in surface preparation. You may also have to use a known material for a reference. The energy spectrum of the photo-emitted electrons you get will be related to the valence band structure. Some details will depend on the fermi level of the material. So it is a very useful technique, but not usually used to get the band gap by its self.
Dear John , have you ever done such a measurements With UPS ? if so what do you think about multi layers and thin films and their measurements ? Also cleaning the surface can mislead the their measurement results ? what do you think ?
National Center for Nanoscience and Technology
Universiti Malaysia Pahang
Indian Institute of Technology Delhi
Hilal S. Wahab
Georgia Institute of Technology
National Research Council
University of New Mexico
Mumbai Educational Trust
Gonzalo Angeles Ordóñez
Universidad Nacional Autónoma de México