Evidence of nitric-oxide-induced surface band bending of indium tin oxide

The interaction of indium tin oxide (ITO) film with nitric oxide (NO) has been investigated in situ by a four-point probe and x-ray photoelectron spectroscopy (XPS). The XPS N 1s peak emerged at a high binding energy of 404 eV indicating that NO was molecularly adsorbed on ITO surface. The adsorption of NO on ITO surface also induced a 0.2 eV shift in its valence band maximum to the low binding energy side leading to an upward surface band bending. We have shown that the increase in the ITO sheet resistance was attributed to its surface band bending. (C) 2004 American Institute of Physics.