Formation and Schottky Barrier Height of Au Contacts to CuInSe2

Synchrotron radiation soft x-ray photoemission spectroscopy was used to investigate the development of the electronic structure at the Au/CuInSe₂ interface. Au overlayers were deposited in steps on single-crystal p and n-type CuInSe₂ at ambient temperature. Reflection high-energy electron diffraction analysis before and during growth of the Au overlayers indicated that the Au overlayer was amorphous. Photoemission measurements were acquired after each growth in order to observe changes in the valence band electronic structure as well as changes in the In 4d and Se 3d core lines. The results were used to correlate the interface chemistry with the electronic structure at these interfaces and to directly determine the Au/CuInSe₂ Schottky barrier height.