Corundum Structure Oxides Studied by XPS

Abstract

The electronic structure behaviour of Me,O, oxides (Me = Ti, V, Cr) has been determined from X P S valence band and core level measurements. From Ti to Cr sesquioxide the relative intensity of the 3d band increases systematically which can be explained by the (atomic) photoelectric cross section and the number of 3d electrons. Simultaneously the 3d-2p band separation decreases indicating a more stronger band overlap equivalent an enhanced covalent bonding component. The different electrical properties among the corundum structure oxides are determined by the trigonal field splitted and eg orbitals, their occupation and relative energy position at the Fermi level. The observations confirm the change from itinerant to more localized behaviour of d electrons caused by crystal structure parameter change (c/u ratio).

Evaluation of microwave plasma oxidation treatments for the fabrication of photoactive un-doped and carbon-doped TiO2 coatings

“…The oxidized surface layer is confirmed to be TiO 2 with the expected peaks for Ti 4+ (Ti2p 1/2 at 458.5 eV and Ti2p 3/2 at 464.2 eV) and O 2-(529.7 eV -The peak at 531.3 eV is due to surface hydroxyl groups) exhibited in the spectra [12][13][14][15]. Similar peaks were observed for all oxidized titanium surfaces.…”

Analysis of XPS spectra of Fe2+ and Fe3+ ions in oxide materials

“…This structural similarity can be seen in many transition metal oxides. For examples, the binding energies of Ti 3p are 36.0 and 37.5 eV for Ti 3+ and Ti 4+ , respectively [25,26], those of Mn 3p are 49.5 and 50.2 eV for Mn 3+ and Mn 4+ [27] and those of Co 3p are 60.2 and 61.1 eV for Co 2+ and Co 3+ [28]. Therefore, the method to determine Fe 2+ and Fe 3+ atomic ratios developed in this study may be applicable to other transition metal oxides systems.…”

The microstructure investigation of GeTi thin film used for non-volatile memory

“…4 presents the XPS spectra of Ti 3p and Ge 3d. The BE values reported for Ti 4+ 3p, Ti 2+ 3p, Ge 4+ 3d, and Ge 0+ 3d were 37.5, 36, 32.5, and 29 eV, respectively [22][23][24][25]. In Fig.…”