Defects in the alkaline earth oxides

O−holes associated with alkali acceptors inBaTiO3Varnhorst1, Schirmer2, Kröse3 et al. 1996Phys. Rev. B674360View full textAdd to dashboardCite

“…These g-tensor components are typical for O Ϫ trapped hole centers. 9 Since the g values closest to g e , the free electron g value, are expected for B along the symmetry axis of an O Ϫ p lobe, the model in Fig. 2 is consistent with the observed angular dependence.…”

Intrinsic Luminescence of the Undoped Glasses of (CaO-Ga2O3-GeO2) System

“…The emission bands of the F+ and F centres with maxima at about 380 and 620 nm, respectively, were observed in CaO crystals under excitation in their absorption bands [21]. The photoexcited emission bands in additively coloured Ca3Ga2Ge3O12 crystals are interpreted as luminescence of the F+ centres (a maximum near 450 rim) and the electron-hole recombination on Gat kra antisite defects (a maximum near 360 nm) [7].…”

“…different oxide compounds we suppose that the UV-excited complex broad emission bands with maxima at roughly 500 nm and 420 nm in the (CaO-Ga2O3-GeO2) glasses are due to a release of electrons from oxygen vacancies, which then recombine with an ensemble of the transient O -hole centres [24,25]. The emission bands with maxima at nearly 380 and 710 nm, which were distinctly revealed in glasses with Ca3Ga2Ge3O14 and Ca3Ga2O6 compositions, may be related with luminescence of two different centres of electron type (analogies of the F+ and F centres in the crystals of simplest oxides [21]). These assumptions are supported by EPR investigations of the UV-irradiated glasses.…”

Search for Origin of Room Temperature Ferromagnetism Properties in Ni-Doped ZnO Nanostructure

“…The cause of this peak is considered as a green emission (504-524nm) is due to the recombination of photo generated hole and the electron trapped by single ionized oxygen vacancies (V o + ), this proof of presence of singly ionized oxygen vacancy states 51,52 . However oxygen vacancies, which are an important class of point defects in oxides and also known as colour centres (F centres) 53 shows three dissimilar charge states, as F 2+ (unoccupied), F + (singly occupied), and F 0 (doubly occupied), in the ZnO lattice. In case of F 2+ and F 0 vacancies have spin-zero ground states; hence they do not induce FM in ZnO 54,55 .…”