The optical band-gap of TiO2increased from 3.36 eV to 3.41eV with increasing milling time (tm) up to 600 min, which was in good agreement with the blue shifts observed in the CL spectra with increasingtmand it was interpreted as a quantum size effect. In addition, the optical band-gap ...
Nanocrystalline TiO2 powders with different optical band gap have been successfully prepared using solution combustion method starting directly from titanium metal. The emphasis is placed on the role of fuel urea on the variations of optical band gap which is obtained from DRS data in the range of...
The optical band gap of 3.03 eV forbulk-rutile increased for the thin films to 3.37 on sapphire. The band gapof 3.20 eV for bulk-anatase increases to 3.51 on SrTiO3.In order to interpret this expansion, ab-initio calculations wereperformed using the Vienna ab-initio software. The ...
[51], by tuning the l-pseudogap of TiO2 inverse opals within titania’s electronic band gap so that the consequent stop band reflection is largely suppressed by the strong TiO2 electronic absorption, while slow photons at the red edge of the stop band enhance the relatively weak optical ...
In all cases, occupied mid-gap states attributed to a hybridization of O-2p with halogen 1 s orbitals were also predicted. Although such states are beneficial for the oxide’s photocatalytic activity as they significantly reduce the optical band gap with respect to that of undoped TiO2, they...
The optical bandgaps of TiO2 and Fe2O3 have been determined to be 3.25 and 2.20 eV, respectively, in Fig. 5. Therefore, the conduction band offset ∆Ec (CBO) at the interface of Fe2O3-TiO2 is estimated to be 1.20 eV. Considering the band structure of TiO2 vs. standard hydrogen ...
The “optical band gap energies” of 1, 2, 3 and 4 layers of TiO2 films were 3.65, 3.60, 3.59 and 3.40 eV, respectively. These properties showed that the multilayer films of TiO2 can be enhanced the properties of optoelectronic devices....
Recent studies indicated that noncompensated cation-anion codoping of wide-band-gap oxide semiconductors such as anatase TiO2 significantly reduces the optical band gap and thus strongly enhances the absorption of visible light [W. Zhu et al., Phys. Rev. Lett. 103, 226401 (2009)]. We used ...
Ge and Nb co-doped anatase TiO_2 films are prepared by using radio frequency magnetron sputtering.The structures,resistivities and band gap properties of the films,which depend on Ge and Nb doping amounts,sputtering power and annealing temperature,are discussed.It is found that the band gap an...
whereαis the absorption coefficient,Eis the photon energy, andEuis the Urbach energy [41,42]. The Urbach energy is calculated by plotting lnαvs.E. The reciprocal of the slopes of the linear portion, below the optical band gap, gives the value ofEu. The Urbach energy of each sample is...