The electronic properties of oxygen vacancies in titania nanotubes were examined

using electron spin resonance spectroscopy. The single-electron-trapped oxygen

vacancy showed a Curie behaviour at 140 to 300K, which was indicative of

localized electrons at the single-electron-trapped oxygen vacancy sites. On the

other hand, the Ti3+ sites showed a thermally activated behaviour with an activation

energy of about 120meV. Microwave saturation measurements revealed the singleelectron-

trapped oxygen vacancy signal to show apparent saturation with

increasing microwave power. In contrast, the Ti3+ signal showed almost

unsaturated behaviour, suggesting Ti3+ had faster spin-relaxation times than the

single-electron-trapped oxygen vacancy. The difference between Ti3+ and singleelectron-

trapped oxygen vacancy appeared to be related to the difference between

the bulk and surface spins.

Electronic Properties of Oxygen Vacancies in Titania Nanotubes. J.M.Cho,

J.M.Seo, J.K.Lee, H.Zhang, R.Lamb: Physica B, 2009, 404[1], 127-30