Anion incorporation and its effect on the dielectric constant and growth rate of zirconium oxides

Rahim, M. A. Abdel; Rahman, A.; Khalil, Munawar

doi:10.1007/bf00242198

Cited by 15 publications

(4 citation statements)

References 22 publications

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“…The dielectric properties of the oxide film formed under the swept potential control were examined in terms of a parallel plate capacitor, eq 4, and in accordance with the high-field growth law, eq 5. According to the “high-field” law, ,,− a linear relationship between the oxide capacitance and formation potential, E f , is expected, since the behavior of bismuth during anodic oxidation resembles the kinetics of anodization of valve metals. − ,− Thus where the second equality stands for and d ox is the oxide layer thickness, α is the anodization coefficient that indicates the rate of oxide growth in nm V -1 , E a,l is the upper (anodic) potential limit, and is the electrode potential at which oxide formation starts. It refers to a hypothetical thickness d ox = 0.…”

Section: Resultsmentioning

confidence: 99%

“…As a result of their applications in areas of optical films, microelectronics, capacitor manufacturing (for electrolytic MOM capacitors), and protection against corrosion, the electrochemistry of most “valve” metals (Al, Ti, Zr, Nb, Ta, Bi, etc.) has been extensively investigated for a long time. − The name “valve” is sometimes used for the range of metals having useful electronic properties for vacuum tube technology.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Electronic and Dielectric Properties of Anodic Oxide Films on Bismuth by Electrochemical Impedance Spectroscopy

Metikoš‐Huković

Grubač

1998

J. Phys. Chem. B

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The results of impedance spectroscopy measurements confirm that different types of anodic films grow on bismuth in slightly alkaline solution and under potentiodynamic and potentiostatic experimental conditions. The band model of solids can describe the behavior of these films. Several approximations were necessary to introduce, since “rapidly” grown oxide films (with α = 22 nm V-1) were highly nonstoichiometric and amorphous in structure. Numerical analysis showed that two capacitive contributions were involved in the measured impedance spectra, the oxide film capacitance (C ox ) and space charge capacitance (C SC), which were used to characterize the semiconducting and dielectric properties of the Bi2O3/electrolyte structure. Both donor concentration (N D) and the critical electrode potential have been determined from Mott−Schottky behavior. The dielectric properties of the oxide film were discussed in terms of a parallel plate capacitor and in accordance with the high-field growth law, and several parameters were determined: the oxide layer thickness (d ox), the dielectric constant (ε), the potential at which oxide electroformation starts ( ), the thickness of native oxide (d in), and the anodization coefficient (α). Potentiostatic anodization confirms the rearrangement within the oxide film under the high electric field detected by impedance spectroscopy. The results indicate that the film formed potentiostatically behaves almost like a capacitor (insulator). The high resistance of the Bi−Bi2O3/electrolyte structure was ascribed to a very high interfacial charge-transfer resistance.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of Electronic and Dielectric Properties of Anodic Oxide Films on Bismuth by Electrochemical Impedance Spectroscopy

Metikoš‐Huković

Grubač

1998

J. Phys. Chem. B

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“…This falls within the wide range of values ͑24.8-55.8͒ found in the literature. [32][33][34][35][36] No trends with time were detected, and it seems that these variations probably represent either the reproducibility of the measurements or the stability of the controlling film property.…”

Section: Discussionmentioning

confidence: 98%

Anodic Oxide Growth and Hydrogen Absorption on Zr in Neutral Aqueous Solution: A Comparison to Ti

Noël

Shoesmith

Tun

2008

J. Electrochem. Soc.

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Anodization and subsequent cathodic polarization of a thin-film sample of Zr were studied with in situ neutron reflectometry and electrochemical impedance spectroscopy ͑EIS͒. The results show the originally 485 Å thick sputter-deposited film generally behaved similar to a bulk electrode in neutral Na 2 SO 4 solution. The anodic oxide, grown by applying 0.5 V potential steps, contained a significant amount of hydrogen in one form or another. The observed anodization ratio was somewhat higher than the literature value determined by coulometry, while the Pilling Bedworth ratio was in good agreement with published data. Oxide layer thickening, accelerated immediately after an anodic polarization was applied, persisted for many hours, suggesting the migration of ions continues for an extended time. The oxide cracked when the applied potential reached 1.5 V and its thickness reached ϳ100 Å, causing loss of passivation. Surprisingly, the EIS behavior of the sample with cracked oxide could still be well represented by a single time-constant equivalent circuit consisting of a capacitor and a leakage resistor, albeit with much lower resistance. This indicates that the cracked and intact regions of the electrode behave essentially independent as parallel electrodes. The proposed modified equivalent circuit can explain a number of other unusual observations, including those seen under cathodic polarization.All the group 4B metals, zirconium, titanium, and hafnium, are known for forming strongly adherent, highly corrosion-resistant passive oxides. These metals owe this property to their s 2 d 2 electronic configuration which gives metal cations in the +4 oxidation state ͑inert gas configuration s 0 d 0 ͒ when protective oxides are formed on the surface of the metals. As originally emphasized by Uhlig since the 1940s, electronic configuration ultimately determines the type and structure of surface oxide films. 1 All three metals, largely due to their corrosion resistance, find unique applications in the nuclear industry: Ti as a potential canister or drip shield material for underground spent nuclear fuel disposal, 2 Zr, with very low absorption of neutrons, 3 as the metal of choice for the calandria and pressure tubes of the CANDU and several other types of reactors, and Hf, with a neutron absorption cross section nearly 600 times that of Zr, 3 in reactor control rods. Interestingly, Zr and Hf are nearly always found together in nature and are two of the most difficult elements to separate, as their chemistry is nearly identical, yet Hf must be thoroughly removed from Zr that is to be used in reactor pressure tubes; because of hafnium's very large neutron absorption cross section, a CANDU reactor made of pressure tubes contaminated even by a small amount of Hf would not start.Both ZrO 2 and TiO 2 are semiconductors with large gaps in the electronic band structure, 5.7 eV 4 and 3-3.4 eV, 5-8 respectively. Although not clean as to semiconductor industry standards, these oxide layers that form on their metals are good insulators...

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“…47 Figure 5 is a model explaining the growth of ZrO 2 as a function of anodisation voltages. This proposed mechanism is adapted from those established by Azuma et al ., 48 Abdel Rahim et al ., 49 and Mamun et al . 50 for anodised Zr foils.…”

Section: Effects Of Applied Voltage On Thin Film Formation Mechanismsmentioning

confidence: 94%

Effects of anodisation parameters on thin film properties: A review

Wong

Affendy

Lau

et al. 2017

Materials Science and Technology

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Electrochemical anodisation is a well-received method in the complementary metal-oxide-semiconductor field as it is advantageous; best performed at room temperature which translates into being more affordable and a simple alternative to form nano-structured oxide films for different metals. The quintessential parameters involved allow numerous formations of metal oxide films according to desired morphology and thickness. Therefore, this paper aims to review the effects of anodising parameters such as applied voltage, concentration, temperature, time, current density and post-anodisation annealing among them.

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Anion incorporation and its effect on the dielectric constant and growth rate of zirconium oxides

Cited by 15 publications

References 22 publications

Characterization of Electronic and Dielectric Properties of Anodic Oxide Films on Bismuth by Electrochemical Impedance Spectroscopy

Characterization of Electronic and Dielectric Properties of Anodic Oxide Films on Bismuth by Electrochemical Impedance Spectroscopy

Anodic Oxide Growth and Hydrogen Absorption on Zr in Neutral Aqueous Solution: A Comparison to Ti

Effects of anodisation parameters on thin film properties: A review

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