Alternation of Ti 2p XPS Spectrum for TiO₂ by Ar Ion Bombardment

Abstract

Angle resolved XPS measurements were performed for a reduced TiO₂ single crystal after Ar ion sputtering with 500 V in order to examine the depth profile of the reduced states. Comparing this angle resolved XPS measurement with the calculation, the component of Ti²⁺ has a gaussian like depth distribution. The component of Ti³⁺ is a localized near surface and smoothly distributed inner layer. Ar ion bombardment with low angle incidence was performed in order to decrease the thickness of the reduced layer. The intensities of the reduced states decreased with lowering incident angle of Ar ion. Moreover, ion bombardment with the low angle incidence has revealed that most of the reduced states are decreased and the intensities of the undamaged Ti⁴⁺ components are increased. These results prove that suitable conditions for the Ar ion sputtering will give a correct depth profile of the chemical states for the compounds which are altered by the ion bombardment.