Physicochemical characterization of passive films on niobium by admittance and electrochemical impedance spectroscopy studies

Quarto, F. Di; Mantia, Fabio La; Santamaria, Monica

doi:10.1016/j.electacta.2005.03.065

Cited by 54 publications

(93 citation statements)

References 20 publications

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“…Therefore, we decided from a phenomenological point of view to use the model proposed by Di Quarto et al [41] in this work. This model was applied for interpretation of amorphous metal oxideelectrolyte interface in [35,43].…”

Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

“…Thus, the Mott-Schottky analysis can be used for amorphous oxide films as long as no major changes occur. Against, Di Quarto et al [41] proposed a model for the interpretation of the impedance responses of anodic semiconductor oxides by applying the amorphous semiconductor theory formulated by Cohen and Lang [42].…”

Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

“…According to the model, proposed by Di Quarto, the total capacitance, under hypothesis of a constant density of states, at low band-bending conditions is defined by the following expression [41]:…”

Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

“…For high band-bending conditions, the following analytical expression for the total capacitance was derived [41]:…”

Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

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Photoelectrochemical properties of MoO2 thin films

Dukštienė

Sinkevičiūtė

2013

J Solid State Electrochem

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Thin MoO 2 films were electrodeposited on a selenium pre-deposited SnO 2 |glass plate. The photoelectrochemical properties of MoO 2 films were investigated in 0.1 M Na 2 SO 4 solution by the ultraviolet-visible spectrophotometry, linear sweep voltammetry, and altering current impedance measurement techniques. It was found that under illumination with the incident light of λ=366 nm, the photo response of the MoO 2 |SnO 2 |glass electrode resulted from the MoO 2 layer, while the SnO 2 layer served as a sink for photogenerated charge carriers. The MoO 2 film exhibited ntype conductivity. A schematic band structure diagram of MoO 2 in 0.1 M Na 2 SO 4 solution was constructed. The flat band potential (E fb ), the donor concentration (N D ), the photogeneration current efficiency depended on MoO 2 film thickness. The [Fe(CN) 6 ] 4−/3− redox PEC cell with MoO 2 | SnO 2 |glass plate as a photoanode was constructed. Power output characteristics such as the open circuit voltage (V OC ), short circuit current (I SC ), the fill factor (FF), and the lightto-electrical conversion efficiency (η) were determined. The maximum light-to-electrical conversion efficiency exhibited by the PEC cell was 0.94 %.

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Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

“…For high band-bending conditions, the following analytical expression for the total capacitance was derived [41]:…”

Section: Photoelectrochemical Performance Of Electrode Smentioning

confidence: 99%

See 2 more Smart Citations

Photoelectrochemical properties of MoO2 thin films

Dukštienė

Sinkevičiūtė

2013

J Solid State Electrochem

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“…9. In order to explain the dependence of C on the polarizing voltage as well as on the a.c., frequency, we have to recall briefly of amorphous semiconductor Schottky barrier, 18,19 which takes into account the influence on the electronic properties of the short range order of amorphous material. In fact, the main difference between crystalline and amorphous semiconductors is that the space charge region width, x SC , depends on both the ionized impurities and the localized states within the mobility gap.…”

Section: Metallic Substratementioning

confidence: 99%

Characterization of the Solid State Properties of Anodic Oxides on Magnetron Sputtered Ta, Nb and Ta-Nb Alloys

Franco

Zampardi

Santamaria

et al. 2011

J. Electrochem. Soc.

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Tantalum oxide, niobium oxide and Ta-Nb containing mixed oxides were grown by anodizing sputter-deposited Ta, Nb and Ta-Nb alloys of different compositions. A photoelectrochemical investigation was performed in order to estimate the band gap and the flat band potential of the oxides as a function of their composition. The band gap of the investigated Ta-Nb containing mixed oxides changed monotonically between those estimated for Ta 2 O 5 (4.1 eV) and Nb 2 O 5 (3.4 eV) and in agreement with a proposed correlation between the Band gap of an oxide and the difference of electronegativity of the oxide constituents. From the differential capacitance curves recorded in a wide range of electrode potential and for several frequencies of the alternative signal, the dielectric constant of the investigated oxides were estimated. © 2011 The Electrochemical Society. [DOI: 10.1149/2.031201jes] All rights reserved. Microelectronics is very important for almost all kinds of technology evolutions in the past four decades. In this area, the dielectrics science occupies a prominent place in providing the dominant technology in integrated capacitors or gate insulators. In the last years the main challenge has been to scale down the insulating oxide thickness keeping low values of the leakage current. This task has been partially achieved for metal-oxide-semiconductor field effect transistor thanks to the use of hafnium based dielectrics, while less has been done for dynamic random access memory and metal-insulator-metal capacitors (DRAM MIMCAP). To the last generation DRAM, very low (from 0.5 to 0.35 nm) equivalent thickness is required with the constraint to maintain a very low leakage current. This implies the use of material having high dielectric constant (∼50) and high band gap (>4 eV), which can be obtained by post formation thermal treatment and tuning of the oxide composition. Owing to their high value of dielectric constant, Ta 2 O 5 and Nb 2 O 5 are quite attractive oxides for the development of the next generation of DRAM. Tantalum oxide is a wide band gap (∼4 eV) material with a high dielectric constant (ε = 27 -30) if properly crystallized (T > 750• C). Niobium oxide has a higher dielectric constant (ε = 53) with respect to Ta 2 O 5 but a lower band gap (∼3.3 eV). In recent papers, 1-3 it has been shown that the addition of small amount of Nb in tantalum based oxide decreases the crystallization temperature with small effect on the band gap value of the material. Thus, (Nb (1−x) Ta x ) 2 O 5 have been introduced in the International Technology Roadmap for Semiconductors (ITRS).Tantalum-niobium mixed oxides for microelectronic components are usually prepared by high vacuum techniques (physical and chemical vapour depositions, atomic layer deposition). [4][5][6][7] In this work we propose to prepare these oxides by anodizing in suitable solutions sputter-deposited Nb-Ta alloys. This electrochemical room temperature process allows to grow oxides of controlled thickness and composition, even if a detailed investigation on t...

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Valve Metal, Si and Ceramic Oxides as Dielectric Films for Passive and Active Electronic Devices

Michaelis

2008

Advances in Electrochemical Sciences and Engineering

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Physicochemical characterization of passive films on niobium by admittance and electrochemical impedance spectroscopy studies

Cited by 54 publications

References 20 publications

Photoelectrochemical properties of MoO2 thin films

Photoelectrochemical properties of MoO2 thin films

Characterization of the Solid State Properties of Anodic Oxides on Magnetron Sputtered Ta, Nb and Ta-Nb Alloys

Valve Metal, Si and Ceramic Oxides as Dielectric Films for Passive and Active Electronic Devices

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