Photoelectron spectroscopy investigation of NO adsorption on defects of LiNbO3 surfaces

The differences of NO adsorption on surfaces of single crystals of LiNbO3 treated by a preheating stage at 400°C in a vacuum chamber and by Ar ion sputtering have been investigated with X-ray photoelectron spectroscopy (XPS). The surface composition of a single crystal of LiNbO3 changed to LiNb3O8 after the preheating at 400°C for 1 h, and NO was chemisorbed as NO2− and NO3− at room temperature on this surface. The surface of the single crystal sample was reduced, until View the MathML source of niobium ion was shifted to Nb4+ and Nb3+ from Nb5+ after Ar ion sputtering for 10 min. NO was chemisorbed at room temperature on this defective sample, and reacted mainly as LiNO3, though, small peaks of NO− and a dissociated N atom were also observed on the N1s spectrum of XPS.