X-ray Photoelectron Spectroscopy Studies of ITO Thin Films

The chemical states of In, Sn and O in Sn-doped In_2O_3 films were investigated byusing X-ray photoelectron spectroscopy. The results indicate that Sn and In respectively exist ina same chemical state for both as-deposited and post-annealed films. Two types of O~2-ions, O_iand O_II, can be distinguished by Gaussian simulation. O_I has a binding energy of 529.90±0.30 eVwhich is in oxygen sufficient region, and O_II has a binding energy of 531.40±0.2 eV which is inoxygen deficient regions. Oxygen deficient regions mainly exist in the surface layer.