Four different Nb4+ centers in niobium-doped zinc tungstate single crystals have been observed by ESR after thermal reduction or electron irradiation. These centers, which are electron-like, exhibit C1 symmetry rather than the C2 symmetry of the cation lattice sites. The reduction in symmetry is attributed to charge-compensating C and OH containing complexes near the Nb4+ ions. Electron irradiation also produces some hole-like Nb defects.
ASJC Scopus subject areas
- Physics and Astronomy(all)