Electrical transport in rare-earth oxides

Rao, G. V. Subba; Ramdas, S.; Mehrotra, P.N.; Rao, C. N. R.

doi:10.1016/0022-4596(70)90095-2

Cited by 107 publications

(37 citation statements)

References 22 publications

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“…From a consideration of the nonstoichiometric rare earth oxides to be electron hopping, the phenomenon that the conductivity in LnO x becomes the highest about x ) 1.75 can be calculated as is obtained experimentally. 133 Among LnO x systems, the composition of LnO 1.75 seems to hold a random distribution of both Ln 3+ and Ln 4+ ions in such a manner to show a maximum electronic disorder. The mechanism of the conduction has been interpreted in terms of the hopping process 135 and of intermediate polaron theory.…”

Section: A Electrical Propertiesmentioning

confidence: 98%

The Binary Rare Earth Oxides

1998

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Section: A Electrical Propertiesmentioning

confidence: 98%

The Binary Rare Earth Oxides

1998

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“…Pr oxides form a number of so-called nonstoichiometric phases in the stoichiometry range between PrO x with x = 1.5 ͑Pr 2 O 3 ͒ and x =2 ͑PrO 2 ͒ with semiconducting properties changing from p-type ͑x Ͻ 1.75͒ to n-type ͑x Ͼ 1.75͒. [52][53][54][55][56][57] Unfortunately, the reported activation energies of n-type conduction in PrO 2 substantially scatter, namely, from 0.8 ͑Ref. 55͒ to 2.1 eV, 56 so that a correlation with our study is at present difficult.…”

Section: B Electrical Characterizationmentioning

confidence: 99%

Dielectric properties of single crystalline PrO2(111)/Si(111) heterostructures: Amorphous interface and electrical instabilities

Seifarth

Walczyk

Łupina

et al. 2009

Journal of Applied Physics

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Single crystalline PrO 2 ͑111͒ / Si͑111͒ heterostructures are flexible buffers for global Ge integration on Si. A combined materials science-electrical characterization is carried out to study the influence of postdeposition annealing in 1 bar oxygen at 300-600°C on the dielectric properties of PrO 2 ͑111͒ / Si͑111͒. The materials science transmission electron microscopy and x-ray reflectometry studies reveal that postdeposition oxidation of the PrO 2 ͑111͒ / Si͑111͒ boundary results in an amorphous interface ͑IF͒ layer, which grows in thickness with temperature. Nondestructive depth profiling synchrotron radiation-based x-ray photoelectron spectroscopy and x-ray absorption spectroscopy methods demonstrate that this amorphous IF layer is composed of two Pr-silicate phases, namely, with increasing distance from Si, a SiO 2 -rich and a SiO 2 -poor Pr silicate. The electronic band offset diagram shows that the wide band gap dielectric Pr silicate results in higher band offsets with respect to Si than the medium band gap dielectric PrO 2 . The electrical characterization studies by C-V measurements show that ͑a͒ well-behaved dielectric properties of the PrO 2 ͑111͒ / IF/ Si͑111͒ are achieved in a narrow postdeposition oxidation window of 400-450°C and that ͑b͒ defects are distributed over the Pr-silicate IF layer. Temperature-dependent J-V studies report furthermore that the formation of the single crystalline PrO 2 /amorphous Pr-silicate bilayer structure on Si͑111͒ results in ͑a͒ improved insulating properties and ͑b͒ strong electrical instability phenomena in the form of a Maxwell-Wagner instability and dielectric relaxation.

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“…Here, heavier is the rare earth, lower is the conductivity. 6 Concerning the thermodynamic properties, the rare earth sesquioxides have been commonly assumed to vaporize congruently with a composition in agreement with almost the stoechiometry ratio. 4 The gaseous rare earth oxide species of the general formulas RO, R 2 O, RO 2 and R 2 O 2 have been observed.…”

Section: Introductionmentioning

confidence: 99%