Defects which were 0.5 to 0.8eV below the conduction band edge, contributing to trap-assisted tunneling and Frenkel–Poole transport, were reported for injection from n-type Si into SiO2–HfO2 dielectrics. Band-edge spectroscopic measurements, combined with X-ray absorption spectroscopy, identified localized defect states at this energy below the conduction band edges of HfO2, and ZrO2. Cathodoluminescence and capacitance–voltage studies, combined with band-edge spectroscopy, identified an interfacial trap which was associated with O vacancies.

Intrinsic Nanocrystalline Grain-Boundary and Oxygen Atom Vacancy Defects in ZrO2 and HfO2. G.Lucovsky, C.L.Hinkle, C.C.Fulton, N.A.Stoute, H.Seo, J.Lüning: Radiation Physics and Chemistry, 2006, 75[11], 2097-101