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Broadband dielectric spectroscopy of Al/Lu2O3/Al thin film sandwiches

Wiktorczyk T.

Materials Science Poland

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2009

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Vol. 27, No. 4/2

1179--1187

EN

The paper focuses on the dielectric characterization of electron beam deposited lutetium oxide thin films sandwiched between aluminium electrodes. The complex capacitance characteristics were recorded in the frequency domain (from 10 žHz to 10 MHz) with a dielectric response analyser. The influence of the temperature, the insulator thickness and sample ageing on C´(?) and C"(?) characteristics was examined. It was shown that high frequency/low temperature dielectric data are assigned to the volume of lutetium oxide film, whereas the low frequency/high temperature results are connected with M/I interfaces. The width of near electrode regions (Schottky barriers) was estimated (? ? 2.6-4.7 nm).

2

Effect of silica precursors-type on mechanical properties of sol-gel coatings

Grygier D., Dudziński W., Wiktorczyk T., Haimann K.

Acta of Bioengineering and Biomechanics

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2008

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Vol. 10, nr 1

27-35

EN

Reversion to narrowing, called restenosis, still remains an important problem of coronary angioplasty. Analysis of the problem revealed that the application of surface layers aimed at creating on the stent surface a neutral barrier between its metallic framework and tissues of the blood-vascular system is decidedly best to impede the restenosis. They also play the role of medicine carriers. This article presents a new sol-gel technology, to be applied in coronary stent coatings. Currently, this is one of the most progressive methods allowing the modification of surface layers of metallic biomaterials. The results presented prove that due to a proper selection of silica precursors it is possible to obtain continuous, smooth, plastic deformation-resistant sol-gel coatings, which additionally are characterised by very close adherence to the base material, nanometer thickness and low degree of surface development.

3

Broadband dielectric spectroscopy of ALl/Lu2O3/Al thin film sandwiches.

Wiktorczyk T.

Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje

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2007

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Vol. 46, nr 19

82-85

EN

The paper focuses on the dielectric characterization of electron-beam deposited lutetium oxide thin films sandwiched between aluminium electrodes. The complex capacitance characteristics were measured in the frequency domain (from 10/xHz to 10MHz) with dielectric response analyser. The influence of the temperature, the insulator thickness and sample aging on C'(u>) and C"((D) characteristics was examined. It was shown that high-frequency/low-temperature dielectric data are assigned to the volume of lutetium oxide film, whereas the low-frequency/high-temperature results are connected with M/I interfaces. The width of near-electrode regions (Schottky barriers) was estimated (k = 2.6-4.7 nm).

4

Rare earth oxide films: their preparation and characterization

Wiktorczyk T.

Optica Applicata

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2001

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Vol. 31, nr 1

5-33

EN

Summarises the results of our investigations dealing with preparation of rare earth oxide films and examinations of their physical properties. Different deposition methods have been applied for fabrication of these films and rare-earth-oxide-based thin film coatings. The main results concerning film microstructure and optical properties in the wavelength range from the UV up to the IR are presented. Electrical and dielectric studies have been carried out in the time domain and in the frequency domain (from very low frequencies up to radio frequencies) for selected rare earth oxides. MIM sandwich-type structures have been fabricated for this aim. Trapping levels in these oxides have been investigated. The complex impedance diagnostics was applied to the analysis of the volume of the R/sub 2/O/sub 3/ film and interfacial properties (metal/insulator barriers) of M/R/sub 2/O/sub 3//M thin film structures.

5

Optical properties of electron beam deposited lutetium oxide thin films

Wiktorczyk T

Optica Applicata

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2001

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Vol. 31, nr 1

83-92

EN

Lu/sub 2/O/sub 3/ thin-film coatings of a thickness 0.1-1.3 mu m were deposited onto quartz plates by an electron beam gun. Optical measurements were carried out for the wavelengths lambda =0.2 mu m-2.5 mu m. All fabricated coatings were highly transparent in the spectral range from 0.3 mu m to 2.5 mu m. Optical constants of Lu/sub 2/O/sub 3/ films have been determined from the spectrophotometrically measured transmittance. The dispersion n( lambda ) and extinction k( lambda ) curves in the spectral range considered have been presented and analysed. The refractive index for Lu/sub 2/O/sub 3/ films has been estimated as 1.84 at 0.55 mu m. The characteristics of the real and imaginary parts of the dielectric function epsilon *(v) are also presented. Values of epsilon '/sub infinity /=323-3.53 have been obtained as the high-frequency optical relative permittivity for Lu/sub 2/O/sub 3/ thin films.