Modern Aspects of Electrochemistry, No. 46

Pyun, Su‐Il; Lee, Jongwon

doi:10.1007/978-0-387-92263-8

Cited by 4 publications

(3 citation statements)

References 105 publications

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“…The dependence of photocurrent on irradiating photon wavelength is not influenced by anodizing electrolyte. By assuming indirect optical transitions the following equation holds: 20,26 I ph hν n ∝ hν − E opt g [3] in which I ph is proportional to the light absorption coefficient and hν is the photon energy. According to Eq.…”

Section: Resultsmentioning

confidence: 99%

“…As already found for other valve metal oxides and also reported for anodic films on sputtering-deposited Hf, such photocurrent can be attributed to photoemission phenomena, involving electrons of the metallic hafnium promoted to the conduction band of the oxide. In such case the dependence of I ph on photon energy is described by the Fowler law: 20,21,36…”

Section: Resultsmentioning

confidence: 99%

“…The experimental set-up for photoelectrochemical investigations was described elsewhere. 20,21 A 450 W UV-Vis xenon lamp, joined with a monochromator, allows irradiation of the working electrode through a quartz window. A two-phase lock-in amplifier was used, coupled with a mechanical chopper (chopping frequency = 13 Hz) that enables the separation of photocurrent from the total current circulating in the cell.…”

Section: Methodsmentioning

confidence: 99%

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Physico-Chemical Characterization of Anodic Oxides on Hf as a Function of the Anodizing Conditions

Zaffora¹,

Tranchida²,

Franco³

et al. 2016

J. Electrochem. Soc.

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Anodic films were grown to 5 V (Ag/AgCl) on mechanically polished Hf in 0.1 M ammonium biborate and 0.1 M NaOH. Independent of the anodizing conditions, the photoelectrochemical characterization allowed the observation of optical transitions at 3.25 eV, i.e. at photon energy lower than the band gap of HfO 2 . They are attributed to localized states inside the gap of the oxide induced by the presence of oxygen vacancies. From the cathodic photocurrent spectra, it was possible to estimate an energy threshold of ~ 2.15 eV for internal electron photoemission phenomena. The impedance measurements proved the formation of insulating oxides with ε = 19.The anodizing occurs under a high field regime with an activation energy of 1.1 eV and an activation distance of 3.8 Å.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Physico-Chemical Characterization of Anodic Oxides on Hf as a Function of the Anodizing Conditions

Zaffora¹,

Tranchida²,

Franco³

et al. 2016

J. Electrochem. Soc.

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Effect of citrate anion incorporation on dielectric properties of anodic oxide grown on Ti-Si alloy

Tranchida,

Zaffora,

Di Franco

et al. 2024

J Solid State Electrochem

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Anodic oxides were galvanostatically grown on sputtered Ti-12at%Si alloy at 5 mA cm−2 up to 50 V in phosphoric acid and sodium citrate aqueous electrolytes in order to investigate the effect of anions incorporation (if any) on dielectric properties of the grown oxides. Photoelectrochemical measurements supported the occurrence of incorporation of citrate anions when anodizing is carried out in a citrate-containing solution. Indeed, two different absorption thresholds were estimated due to energy transitions involving localized states in the mobility gap. Differential capacitance measurements showed higher capacitance values for anodic oxide grown in the citrate-containing solution, with a beneficial effect on the dielectric constant. The increased capacitance can be explained considering the synergistic effect of a more favourable anodizing ratio provided by the presence of Si cations from the bare alloy as well as the incorporation of foreign species due to the inward migration of citrate anions from the electrolyte during the anodizing process.

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Erroneous p-type assignment by Hall effect measurements in annealed ZnO films grown on InP substrate

Macaluso

Mosca

Calı̀

et al. 2013

Journal of Applied Physics

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We report on incorrect carrier type identification achieved by Hall effect measurements performed on ZnO films grown by pulsed laser deposition on InP substrates and subsequently annealed for 1 h at 600 °C in air. While Hall measurements, after post-growth annealing, reveal a change in the electrical properties of the films, from n-type to p-type, both photocurrent-based and standard C−V measurements performed on the same samples show no change in the native n-type doping of the ZnO films. A possible interpretation of the two results is reported. In particular, p-type conductivity observed by Hall effect may be ascribed to a highly conductive thin layer formed during the annealing process at the ZnO/InP interface, which dominates the Hall effect measurements and does not influence the photo-electrochemical behavior of ZnO as well as the measured differential capacitance. The conflicting results here reported show that for this kind of samples, Hall effect measurement can be misleading with respect to the real nature of the analyzed material, instead both C−V and photocurrent-based characterization techniques are more reliable and therefore could be alternatively used when particularly ambiguous results are expected by Hall effect measurements.

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Modern Aspects of Electrochemistry, No. 46

Cited by 4 publications

References 105 publications

Physico-Chemical Characterization of Anodic Oxides on Hf as a Function of the Anodizing Conditions

Physico-Chemical Characterization of Anodic Oxides on Hf as a Function of the Anodizing Conditions

Effect of citrate anion incorporation on dielectric properties of anodic oxide grown on Ti-Si alloy

Erroneous p-type assignment by Hall effect measurements in annealed ZnO films grown on InP substrate

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