eV For TiO2 Research Articles

The formation and properties of heterostructures based on titanium dioxide films volume-doped with palladium particles

Photoelectrochemical and electrophysical properties of semiconductor heterostructures based on TiO 2 films with Pd particles distributed thoughout the bulk of the oxide have been investigated. These heterostructures were prepared by pyrolysis of titanium resinate and PdCl 2 mixture followed by reduction thermal treatment. The reduction process in the TiO 2-Pd films takes place not only in the surface layer but in the entire volume as well and TiO 2 films possess a high donor concentration (N d ~ 10 20 − 10 21cm −3). Here, the TiO 2 energy gap determined from quantum yield spectra increases due to the Burstein shift from 3.11 eV for TiO 2 films to 3.21 eV for heterostructures.

An XPS study of amorphous and crystalline Cu50Ti50 alloy

The surface compositions and chemical states of an amorphous and a crystalline Cu50Ti50 alloy have been analysed by XPS. The Ti element was oxidised on the surface of the as-quenched Cu50Ti50 alloy. The binding energies of the Ti 2p1/2 and Ti 2p3/2 peaks of the as-quenched amorphous Cu50Ti50 were 464.8 and 459.2 eV; these values correspond to 464.1 and 458.6 eV for TiO2. The titanium was thought to be Ti4+ present on the surface of the sample because of the value of the shift in binding energy, Delta (BE). A Ti2p3/2 shoulder peak of the sample appeared at 457.8 eV. The Ti here was thought to be Ti3+, because of the value of Delta (BE). The O 1s1/2 peak showed a double structure, whereas after sputtering only a single peak was observed. The Cu peaks were barely detectable on the surface of the as-quenched sample, but they could be observed on the sputtered surface.

Relation of bonding and electronic band structure to the creation of lattice vacancies in TiO

The relationship between bonding and electronic band structure in TiO is examined and it is found that a high equilibrium lattice vacancy concentration is energetically favorable. Lattice vacancies in TiO allow crystallization as a defective rock-salt type structure, emptying high-energy orbitais by reducing the effective number of valence electrons, which lowers the Fermi energy. Structural stability and mechanical properties of TiO, TiN and TiC are related to the position of the Fermi level, which for 100 per cent dense crystals of TiN and TiO would be forced to lie across antibonding levels. Consideration of energy band calculations by BILZ shows that lattice vacancies lower the Fermi energy by an amount (1.75 eV for TiO) which exceeds the total energy required to create a single titanium or oxygen vacancy (0.31 eV). In this process primarily antibonding orbitais are emptied giving for stoichiometric TiO a net reduction of ca. 1.1 eV in the free energy at absolute zero.