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The development of defect analysis for inorganic semiconductors in the past century paved the way for the success story of today’s electronics. By analogy, defect analysis plays a critical role in ...

Graphite finds use in a large amount of nanoscale applications, including as a substrate for thin film and nanomaterial deposition. With its excellent properties for usage in nanoscale and given the regularity of structure of highly oriented pyrolytic graphite (HOPG), the possibility of use to acquire more precise and detailed results is high. To this end the basic topographical and structural properties of HOPG and thin Fe2O3 have been explored. Methods used were atomic force microscopy, ellipsometry and x-ray photoelectron spectroscopy. Documentation of the results allows for further examination of HOPG usage possibilities, uncoated or coated with Fe2O3 thin film, as well as a substrate for carbon fiber or nanotube growth in future projects.

Nanostructured scattering arrays for the optical spectral domain can be used as passive tags for information encoding, similarly to the manner in which RFID technology does. Setting up their specific spectral response depends on their geometry and the properties of the building materials. The primary design can be provided by using an analytical calculation procedure that is more straightforward and simpler than a numerical simulation. However, the question arises as to the validity of the results. Both approaches are examined in this article. Complementary scatterer arrays were designed using simplified analytical calculation and by means of numerical modeling. The experimental samples were fabricated by the focused ion beam milling of a gold film on a glass substrate and characterized by a spectroscopic system. The results of the analytical calculations, the numerical simulations, and the experimental measurements were compared. On the basis of the comparison, it was observed that for quick array design, both approaches can be used with satisfactory accuracy. Moreover, the simple numerical model also proved the possibility of the identification of the basic dipole mode splitting. Focused ion beam milling was shown to be suitable for the rapid production of complementary scatterer arrays.

Thermal treatment conditions of solid polymer polymer electrolyte (SPE) were studied with respect to their impact on the surface morphology, phase composition and chemical composition of an imidazolium ionic-liquid-based SPE, namely PVDF/NMP/[EMIM][TFSI] electrolyte. These investigations were done using scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry as well as X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. A thoroughly mixed blend of polymer matrix, ionic liquid and solvent was deposited on a ceramic substrate and was kept at a certain temperature for a specific time in order to achieve varying crystallinity. The morphology of all the electrolytes consists of spherulites whose average diameter increases with solvent evaporation rate. Raman mapping shows that these spherulites have a semicrystalline structure and the area between them is an amorphous region. Analysis of FTIR spectra as well as Raman spectroscopy showed that the β-phase becomes dominant over other phases, while DSC technique indicated decrease of crystallinity as the solvent evaporation rate increases. XPS and ToF-SIMS indicated that the chemical composition of the surface of the SPE samples with the highest solvent evaporation rate approaches the composition of the ionic liquid.

This study focuses on the description of oxidation of CdTe monocrystal surfaces after selective chemical etching. Measurements of surface morphology of the oxides occurring in short time are valuable for deeper understanding of the material degradation and fabrication of reliable devices with enhanced performance. The samples with (1 1 1) orientation were selectively etched and cleaned of oxide. Exposure of the oxide-free surfaces of CdTe to air at normal atmospheric conditions over 24 hours leads to an appearance of characteristic surface features. The oxidized surfaces were investigated by scanning electron microscopy, scanning probe microscopy, Raman spectroscopy and ellipsometry. The results indicate clear differences in the oxidation of Cd-terminated and Te-terminated surfaces. Tato studie je zaměřena na popis oxidace monokrystalického povrchů CdTe po selektivním chemickým leptání.

The influence of gamma irradiation on gallium arsenide based photovoltaic cells was investigated. This type of solar cell is used for advanced space application where radiation degradation occurs in particular. A synthetic radioactive isotope of cobalt Co-60 was used with an applied dose of up to 500 kGy. These irradiation cause damage and degradation of the solar cell. A wide range of comparative characterisation methods was performed before and after irradiation. The effect of radiation on material morphology was described using electron and atomic force microscopy. Structural changes were investigated by Secondary Ion Mass Spectrometry (SIMS) with Time-of-Flight mass analysis (TOF) and Raman spectroscopy analysis. Also, the changes in noise fluctuations and current-voltage characteristics of the cell in the dark and under illumination were measured. Based on experimental measurements, the degradation was observed in the structural, optical and material cell properties as well as in electrical parameters.

This work aims to study the surface morphology of solar cells before and after reactive ion etching (RIE) at two different pressures. Two types of solar cell based on GaAs and polycrystalline Si were processed and compared. Energy Dispersive X-ray spectroscopy (EDS) was used for the composition analysis of the samples. Raman spectroscopy showed a structural fingerprint of materials before and after processing. Atomic Force Microscope (AFM) demonstrated dimensional topography with high resolution. Optical spectrometer detected changing of reflectance the samples. Experimentally, it has been confirmed that GaAs solar cells have a very high endurance to ion bombardment in comparison to Si cells.

We report on the temperature dependence of optical response of pure bcc iron and CrNiAl steel. Ellipsometric spectra, covering the 1.4-3.0 eV spectral range, have been obtained during temperature cycles reaching 650 C in UHV chamber. Since the penetration depth of light is rather small and the data are sensitive to the quality of sample surfaces, we have examined polished, etched and annealed samples. We identify characteristic features of the temperature dependence, consisting in spectral shifts of interband transitions and a redistribution of spectral weight. We have also detected reproducible irreversible changes in the initial stages of annealing cycles when the samples are heated to at least 300 C. With increasing temperature, we observe a pronounced reduction of the minority-spin interband contribution.

We present a comparative study of UV degradation of poly[methyl(phenyl)silane] (PMPSi) thin films on Si substrate in HV and in the air. When exposed to UV light with energies around 3.6 eV, the Si backbone scission occurs. The degradation rate is influenced by the presence of oxygen, which is bonded to the Si atoms following the backbone scission. In our experiments, the samples were placed in an HV chamber and ellipsometric spectra were continuously recorded in the 3.3–5.0 eV range. The combined tungsten (halogen)-deuterium source ensuring a proper level of light intensity used for both exposition and measurement. During 100 hours exposures at atmospheric pressure, the PMPSi film degraded completely and its optical response did not change further. Degradation of the sample exposed in vacuum (at the pressure of 5 × 10–6 Pa) is slower and stops earlier. Ellipsometric technique allowed us to perform detailed studies of the degradation dynamics. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

In the paper in situ monitoring of the UV-light- and thermal-treatment of PMPSi thin films by real-time spectroscopic ellipsometry and XPS is reported. The films were treated both under ultrahigh vacuum and oxygen atmosphere. The results of this study indicate that the Si‐Si bonds in the polymer main chain (Si-backbone) were primarily broken at the UV-light treatment. However, the Si radicals recombined into the polymer-like chains causing no remarkable chemical shifts. The UV-light treatment under enhanced sample temperature (≈80 ◦ C) in oxygen atmosphere resulted in the more intense degradation of the PMPSi film. This can be related to cutting off the volatile methyl groups from the polymer main chains. Copyright  2004 John Wiley & Sons, Ltd.

Comprehensive study of the temperature dependence of ultraviolet-visible ellipsometric spectra of thin films of poly(methyl-phenylsilane). It was found the threshold of irreversible changes of its optical response at 373 K and furthermore the average temperature shift of the lowest excitonic band in the reversible regime.The effect of annealing below and above 373 is studied with low- a high-level of the exposure to UV light.

In the paper the application of a simple spectroscopic ellipsometer for ex situ and in situ studies on SiO2 films (including native oxides on Si) is reported. It is shown that the ellipsometer is a reliable tool for the monitoring of chemical etching of SiO2 films with thicknesses of >10 nm. When the films become thinner, the results are strongly influenced by the contamination and roughness of their surface layers. The concentration profiles of these ultrathin films (

In this paper an instrument based on combining the principles of both spectral and multiple-wavelength reflectivity, designed by our group for in situ monitoring of the surface homogeneity of the thickness of weakly absorbing thin films, was tested in a series of ex situ and in situ experiments. The tests confirmed that it is a convenient tool for the in situ quasi-real-time monitoring of the surface homogeneity of the thicknesses of small-area thin films (up to 1 cm2) during their etching and growth. Using this method, homogeneous growth of an SiO2 film with an average growth rate of 103 nm h−1 in one pilot point during deposition by ion beam sputtering of a quartz target was monitored in situ. On the other hand, the ion beam etching rate of the thermal SiO2 film was

We study the anisotropic response of highly oriented pyrolytic graphite (HOPG) in mid-infrared range, utilizing the potential of spectroscopic ellipsometry. We aim at the parameters of the infrared-active vibrations of E(1u) and A(2u) symmetry, and examine the phenomena related to the strong uniaxial anisotropy of HOPG. We explain the appearance of the weakly polar out-of-plane vibration in the elipsometric spectra taken on cleaved planes. We find a detectable Fano-type behavior of the in-plane phonon.

Cobalt and nickel magnetic films were prepared by ion-beam assisted deposition method (IBAD). The main goal of the work was to study the influence of the assisting low-energy-argon-ion beam and substrate temperature on the characteristics and properties of the films, in particular on thickness, roughness, chemical composition, structure and magnetic properties of thin films. The experiments revealed that the assisting argon ions influence most remarkably an in-plane magnetic anisotropy of the films. On the other hand, enhanced substrate temperatures suppress the anisotropy of the films. Influence of these two deposition parameters on roughness, composition and structure of thin films was not dramatic.

The results of a systematic spectroellipsometric and conductivity study of metallic titanium nitride thin films grown on silicon by the ion-beam-assisted deposition technique are presented. The directly measured electrical resistivity is correlated with the contactless, non-invasive ellipsometric method of extracting the free- and bound- carrier response in the infrared, visible, and ultraviolet spectral ranges. The d.c. resistivity of TiN films ranges from ∼100 to ∼500 μΩ cm. The high polarizibility of free carriers at optical frequencies presents non-trivial problems of the measurement optimization. The merit of the ellipsometric data taken at proper angles of incidence in different spectral ranges is discussed for homogeneous and graded layers. For TiN films of a good structural quality, the extrapolation of ellipsometric results is found to be in a fair agreement with d.c. data, providing an optical, contactless way of measuring the electrical conductivity. This can be achieved even with a very simple near-infrared ellipsometer.

Nitrides of metallic elements like Ti, Mo and Al were synthesized by ion beam-assisted deposition (IBAD). This technique was provided via dual ion beam deposition method in an apparatus based on two Kaufman ion beam sources. In our study an influence of the energy of assisting nitrogen ions (50–400 eV) and of the substrate temperature (up to 400°C) on the characteristics and properties of deposited thin films (roughness, thickness, chemical composition, structure, electrical and optical properties, etc.) was investigated. Different ex situ analytical techniques and measurements such as XPS, RBA, XRD, STM, profilometry, ellipsometry and other methods were applied. The composition of thin films prepared by the sputtering of Ti, Mo and Al targets was close to oxinitrides for all ion energies (fluxes). The nitrogen content in all films was increased by assisting ion bombardment; however, it sustained under their stoichiometric values. Structure of all thin films was generally dependent on ion beam energy and substrate temperature. The roughness and thickness (50–400 nm) of the films increased, respectively, decreased with ion energy (flux). Higher substrate temperature (400°C) substantially improved the adhesion of MoN films to silicon substrates. A significant influence of the assisting ion beam on electrical resistivity and index of refraction of Ti–N and Al–N films was observed.

The influence of argon ion-beam bombardment of growing Al, Mo and Ti thin films deposited by ion-beam sputtering on their composition and optical properties was studied. The Ar ion energy and ion-to-atom arrival ratio were 100–600 eV and 0.15–1.75 respectively. The concentration of Mo (A1) in the thin films decreased (increased) with ion energy as the Ar content increased (decreased). The Ti content was below 35% for all ion energies. The ratio O/Ti was close to the stoichiometric value of two for all ion energies up to 400 eV. Higher ion-beam energies and doses led to higher values of the index of refraction for Al and Ti thin films. Furthermore, an increase in the energy of the ions caused a decrease in the deposition rates of all films due to resputtering of the thin film atoms and, in the case of Al thin films, intensified the amorphization process in the Al/Si structure.