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Graphite intercalation compounds (GICs) are widely known for their remarkable multifold physico-chemical properties and their numerous state-of-the-art applications, such as energy storage, sensors, lubrication, catalysis, magneto-optics, superconductivity, etc. However, the properties of GICs largely depend on the synthesis technique, structure, and morphology of the graphite; the size and properties of the intercalant species and its concentration in the host material. Accordingly, in the field of electrochemical energy storage, the appearance of novel ionic systems and detailed investigations of GICs are highly desired. In this study, two different types of graphite, natural graphite (NG) and kish graphite (KG), were used to gain insights into the intercalation of the ClO4− anion in graphite from a concentrated Al(ClO4)3 aqueous electrolyte solution through extensive electrochemical studies and various in situ and ex situ spectroscopic characterization techniques. An analysis of cyclic voltammograms indicated the presence of surface-controlled charge storage along with diffusion-controlled ion intercalation into the interlayer spaces in NG and KG. Additionally, a comparative study on the electrochemical behavior of these two types of graphite showed differences that can be correlated with their structural properties. These findings open new perspectives for GIC formation in concentrated aqueous electrolytes and applications in electrochemical energy storage.

Anodes consisting of Pd and bimetallic PdCu catalysts deposited directly on a carbon cloth by magnetron sputtering have been tested in a direct formic acid fuel cell. Current-voltage measurements showed that a bimetallic Pd-based catalyst temperature-treated to 300 °C exhibits the highest catalytic activity. Chemical and structural information from the surface of the catalysts was revealed by X-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM). Increasing the temperature of the anode together with hydrogen peroxide (H2O2) treatment of the catalyst surface was proposed as an additional treatment method. In this method, the highest catalytic activity was achieved (P = 56 mW mg−1) for a monometallic Pd catalyst. The enhanced catalytic efficiency after these methods had been applied was attributed to the decrease in the content of metal oxide forms, carbon-oxygen groups, and PdCx surface contamination, where the PdCx surface content played a major role.

Copper tungsten oxide films are deposited with the help of reactive high power impulse magnetron sputtering (HiPIMS) in an argon/oxygen gas mixture. Two magnetrons, one equipped with a tungsten target and the other with a copper target, are employed. The HiPIMS discharge is operated with a repetition frequency of [Formula: see text] Hz. Pulse widths of 100 and 20 [Formula: see text]s separated by 25 [Formula: see text]s are chosen for the tungsten and copper target, respectively. Films deposited on two different glass substrates [soda lime glass and fluorine doped tin oxide (FTO) coated glass] are characterized by energy dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, Raman spectroscopy, and ellipsometry. Photoelectrochemical activity was investigated by linear voltammetry. The composition and crystal structure of as-deposited and annealed films are found to depend on the deposition conditions. Annealed films deposited on FTO glass are composed of WO3 and CuWO4 or Cu2WO4 crystal phases. Films deposited on soda lime glass are subject to sodium diffusion into the films during annealing and the formation of Na2W2O7 and Na2W4O[Formula: see text] phases.

We analyze air-exposed and cleaned graphene samples grown by the chemical vapor deposition method on polycrystalline copper. Raman spectra verify their single-layer nature. C 1s and C KVV Auger spectra confirm the dominant C sp2 coordination in the films. We use angular-resolved C 1s, O 1s, and Cu 3p photoelectron spectra to acquire non-destructive concentration depth profiles and for in-depth distribution of resolved bonding states by the Maximum Entropy Method. The elemental distributions show that the air-exposed surfaces of the samples are enriched by carbon- and oxygen- bearing species, resulting in an overlayer 0.6 nm in thickness. The in-depth distributions of the resolved bonding states reveal that the oxygen bonded to carbon is located at the top surface and the oxygen bonded to copper is located at the graphene/copper interface. Almost no oxygen is present at the surface of the samples cleaned by annealing. The percentage of carbon falls by ~40%. The thickness of the carbon overlayer falls to about 0.3 nm, and the graphene layer completely covers the substrate. We emphasize that the results for the in-depth distribution of element concentrations and for resolved chemical bonding states are obtained nondestructively, i.e. without any modifications to surface composition and bonding.

This work attempts to understand the behaviour of Ge-induced cytotoxicity of germanium-doped hydrogen-free diamond-like carbon (DLC) films recently thoroughly studied and published by Jelinek et al. At a low doping level, the films showed no cytotoxicity, while at a higher doping level, the films were found to exhibit medium to high cytotoxicity. We demonstrate, using surface-sensitive methods—two-angle X-ray-induced core-level photoelectron spectroscopy (ARXPS) and Low Energy Ion Scattering (LEIS) spectroscopy, that at a low doping level, the layers are capped by a carbon film which impedes the contact of Ge species with tissue. For higher Ge content in the DLC films, oxidized Ge species are located at the top surface of the layers, provoking cytotoxicity. The present results indicate no threshold for Ge concentration in cell culture substrate to avoid a severe toxic reaction.

Layered nanocomposites with a controlled distribution of mechanical properties across the nanostructure were constructed from oxygen-free (a-CSi:H) and oxygen-bound (a-CSiO:H) individual layers. These were deposited at different power or pulse periods from pure tetravinylsilane and tetravinylsilane in a mixture with oxygen gas using plasma-enhanced chemical vapor deposition operating in pulse mode. XPS depth profiling using argon gas cluster ion beams was used to determine the atomic concentration of carbon, silicon, and oxygen in the individual layers forming the nanocomposite. These layers had a total thickness of about 100 nm. The XPS analysis revealed that the oxygen-free layers were oxidized due to post-deposition oxidation in the ambient air. Oxygen was even diffused in an oxygen-bound layer, which was confirmed by repeated XPS depth profiling within three months after nanocomposite deposition. The upper oxygen-bound layer at the nanocomposite surface behaved as a barrier and reduced oxygen diffusion. The high energy-resolution XPS spectra (C 1s, Si 2p, and O 1s) were analyzed to gain more insight into bonding species formed in layered nanocomposite. This detailed analysis showed that oxygen atoms originating from the ambient air were bound in the oxidized a-CSi:H layers and formed the same bonding states as those in the as-deposited oxygen-bound layers.

Carbon atom coordination at diamond-like carbon (DLC) film surfaces and in sub-surface regions has been determined nondestructively from high-energy resolved C 1s photoelectron spectra, X-ray induced C KVV Auger electron spectra, and angular-resolved C 1s spectra (ARXPS) aided by maximum entropy method (MEM). The spectra were recorded from hydrogen-free DLC films prepared by a pulsed laser deposition under medium energy Ar ion beam assisted growth. The sp3 and sp2 fractions determined from C 1s and C KVV spectra recorded at the normal emission angle differ substantially. This indicates an inhomogeneous depth-resolved distribution of the fractions. The result is validated by the analysis of angular-resolved C 1s spectra using the MEM approach. In-depth reconstructions of the carbon bonding states show that sp2 coordination is dominant at the surfaces. We found that Ar ion beam assisted growth induces a C sp2 peak beneath the surface. The peak shifts towards the surface and is growing with Ar ion energy. C sp3 hybridization is dominant in deeper layers. The in-depth reconstruction is further supported by the depth-dependent mass density determined from the low-loss electron spectra excited at various primary electron energy. The results are discussed within the subplantation model.

Hydrogen free Ti-doped amorphous carbon layers were prepared by dual beam pulsed laser deposition using two excimer lasers. The air-exposed surfaces were analyzed by high-energy resolved and angular-resolved core-level photoelectron spectroscopy, and were then step-by-step sputtered with an argon gas cluster ion beam (ArGCIB), which is known to be a very gentle technique with respect to changes in surface chemistry. The results show that the top surface of the sample and its sub-surface region differ in composition and in bonding. The top surface is enriched by oxygen-bearing species. Carbon-bearing species located on the surface are mostly in sp3 hybridization. Titanium carbide clusters, TiC, are not directly exposed at the surface. They are embedded in a carbon network with dominating C sp2 hybridization. Their interface is formed by a distinct carbon-rich titanium carbide with stoichiometry close to TiC3. The surface damage induced by ArGCIB was found to be minimal, verifiably affecting carbon atoms in the carbon network.

GaP is a preferred candidate for the transition between Si and heterogeneous III-V epilayers as it is nearly lattice-matched to Si. Here, we scrutinize the atomic structure and electronic properties of GaP/Si(0 0 1) heterointerfaces utilizing hard X-ray photoelectron spectroscopy (HAXPES). GaP(0 0 1) epitaxial films with thicknesses between 4 and 50 nm are prepared by metalorganic vapor phase epitaxy on either predominantly single-domain (SD) or two-domain (TD) Si(0 0 1) surfaces. The antiphase domain content in the GaP films is in situ controlled, employing reflection anisotropy spectroscopy. Via the analysis of core level photoelectron intensities, we reveal core level shifts of the P 2p and Si 2p peaks near the interface as well as core level shifts in the Ga 3d peaks near the surface. We suggest an Inter-Diffused Layer (IDL) model of the GaP/Si(0 0 1) interfacial structure with Si P bonds at the heterointerface and residual P atoms in the Si substrate. Using a newly developed Parametrized Polynomial Function (PPF) approach, we derive a non-monotonic band bending profile in the heterostructures, correct experimental valence band offsets implying interfacial electronic barriers, and determine valence band discontinuities of Δ E V = 1.1 ± 0.2 eV (SD samples) and Δ E V = 0.8 ± 0.2 eV (TD samples) at GaP/Si(0 0 1) interfaces.

Thin-film Al filters are very popular owing to their high transmittance in the wavelength range of 17–67 nm and low transmittance in the visible and near-UV regions; however, they are prone to oxidation. The amorphous A l 2 O 3 layers on the Al surfaces have much smaller transmittance than the bulk Al material; therefore, they strongly influence the total transmittance of the filter. This paper not only provides the transmittance of very old Al filters but also maps the transmittance development of Al filters over two years since their delivery (in 2016) in an uncontrolled atmosphere.

The conventional ion beam sputter-cleaning technique is frequently used for removing surface adsorbates and carbon contamination from air-exposed glass surfaces. Due to the ion-surface interaction, however, an altered near-surface layer is formed with a modified composition and modified bonding. In the present work, we first examine changes in surface composition and bonding due to X-ray and electron irradiation for both air-exposed and sputter-cleaned surfaces. Then we apply argon cluster ion beam sputtering, known as a very gentle technique with respect to the changes in surface chemistry, to air-exposed lead-silicate glass surfaces analyzed by high-energy resolved core-level photoelectron spectroscopy. It was found that (i) the surface contamination present on air-exposed lead-silicate glass surfaces has a qualitative influence on the results of an XPS analysis, and (ii) Ar cluster ion beam sputter-cleaning with mean energy per Ar atom in clusters of a few eV was successfully used to remove surface contamination from air-exposed lead-silicate glass with no substantial violation of the glass surface structure. This made it easier to reveal their intrinsic surface properties.

In the present work we determined surface composition and chemical bonds at the top surface and in a shallow sub-surface region of the calcium-doped diamond-like carbon (DLC) layers using angular-resolved photoelectron spectroscopy (ARXPS) aided by the Maximum Entropy Method (MEM). The resulting non-destructive depth profiles showed that the composition and the chemical bonding vary significantly on the way from the top surface to the shallow sub-surface region. We demonstrate, for the first time, that Ca doping induced (i) the accumulation of the calcium carbonate, CaCO3, at the surface, while the calcium oxide, CaO, is located in a deeper sub-surface region, (ii) structural conversion from the C sp2-rich top surface observed in the undoped DLC layer to the C sp3-rich top surface of the Ca-doped DLC samples, and (iii) conversion in the opposite direction which occurred in a sub-surface region. Our conclusions are consistent with Raman and Ion Surface Scattering spectra. Obtained results can be useful for deeper understanding the interaction between doped DLC layer surfaces with surroundings and particularly with living tissue.

Cobalt oxide films were deposited with the help of reactive high power impulse magnetron sputtering (HiPIMS) and mid-frequency pulsed magnetron sputtering (PMS) in argon gas at an argon gas pressure of 1 Pa and with different oxygen admixtures. The HiPIMS discharge was operated at a repetition frequency f=100 Hz with a duty cycle of 1%. Deposition rate and ion fraction were measured. The intensity of plasma ions, in particular Co+ and O+, is enhanced during HiPIMS compared to PMS and extends to larger ion energies. Films deposited on glass substrates were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray diffraction. Crystal structure and electrical resistivity of as-deposited films were found to depend on the deposition conditions. Deposited films are compatible with a non-stoichiometric Co3O4 spinel type crystal structure with unoccupied cobalt sites. PMS produces films with a preferred lattice orientation. HiPIMS show a large internal stress which relaxes during annealing. Electrical resistivity is several orders of magnitude smaller for films deposited by HiPIMS compared to PMS.

Conventional (monoatomic) ion beam sputtering of solid surfaces is currently used for surface cleaning and concentration depth profiling. Due to ion-surface interactions, however, a modified near-surface layer arises, characterized with the changed composition and chemical bonding. As a consequence, this complicates data interpretation. A lot of efforts have been devoted to eliminate the problem. Now, the most promising method seems to be application of multi atomic or molecular ion beams. In the present contribution we examine the influence of argon cluster ion beam on composition and chemical bonding of diamond-like carbon (DLC) and nanocrystalline diamond (NCD) film surfaces by using high-energy resolution core-level photoelectron spectroscopy (XPS). Particularly, peak widths and hybridization of carbon atoms is evaluated from C 1s lines. The extent of bonding transformation from C sp 3 to C sp 2 depended on average energy per Ar atom in the clusters. For the energy as low as a few eV per Ar atom the modification is mild. Prime novelty statement The novelty of the presented research is the examination of the interaction between Argon cluster ion beam with DLC and NCD surfaces via high-energy resolved C 1s photoelectron spectra. Our results show that bonding transformation from C sp 3 to C sp 2 due to Ar cluster ion beam sputtering was found mild, if the average argon atom energy in clusters is comparable to the bond strength of the surface target atoms.

The study of the chemical composition of buried interfaces by X-ray photoelectron spectroscopy (XPS) is limited by the inelastic mean free path of emitted photoelectrons (PE). Soft X-ray sources (AlKα) are generally suitable for careful probing of surfaces or very thin films. Here we applied gas cluster ion beam sputtering in combination with in-situ XPS (GCIB-XPS) to analyze buried GaP/Si(0 0 1) heterointerfaces. The GCIB method was used to dig a crater into the 20 nm thick GaP(0 0 1) film. We found optimal parameters for GCIB sputtering and achieved interface layers without severe damage. Destructive effects, i.e. broadening of core level peaks, could not be completely avoided, however, and the formation of metallic Ga on the GaP surface was observed. PE spectra of the sputtered heterostructures were compared with corresponding reference spectra of sputtered bulk crystals. Interface contributions to the intensity of phosphorus and sillicon core level peaks were revealed: interface components are shifted to high binding energies of P 2p Si 2p core levels. Similar results were obtained on 4 nm thick GaP/Si(0 0 1) by XPS. Finally, a top-to-bottom concept for buried semiconductor interfaces studies by GCIB-XPS is demonstrated.

A lot of research efforts have been invested in the fabrication of superhydrophobic surfaces in recent years due to many protentional applications in science and industry including anti-icing, self-cleaning and anti-corrosive surfaces. Laser as a non-polluting, precise and flexible tool can be applied to replicate surface microstructures of extremely water repellent lotus leave surface. In this study, a common nanosecond laser source is used to fabricate a super/ultrahydrophobic surfaces with different microstructure designs, contact angles above 170° and sliding angles below 5°. The freshly processed surface is hydrophilic and becomes hydrophobic and superhydrophobic in a certain time period, which could be dramatically reduced by storing samples in high vacuum. The transformation in wetting properties are analysed with respect to surface geometry and surface chemistry.

Diamond exhibits good biocompatibility and a large electrochemical potential window, and thus, it is particularly suitable for bio-functionalization and bio-sensing. Modification of the diamond surface can be achieved through mussel-inspired surface chemistry based on polydopamine (PDA) while maintaining the intrinsic properties of the surface. We present a comparative study on the polymerization/deposition of PDA from an aqueous solution of dopamine on hydrogen- (H) and oxygen- (O) terminated nanocrystalline diamond films (NCD). The dopamine polymerization/deposition was performed under mild conditions, which resulted in a confluent PDA layer. A detailed investigation of the growth kinetics of the PDA film on H- and O-terminated NCD substrates was performed using spectroscopic ellipsometry. The chemical composition, the functional group distribution, the surface topography and the wetting properties of the adherent PDA films were evaluated using X-ray photoelectron spectroscopy, atomic force microscopy and water contact angle goniometry, respectively. According to the results, a PDA layer can be used as a platform for future bio-functionalization and/or optical bio-sensing applications.

Multiwalled carbon nanotubes (CNTs) were modified in low pressure capacitively coupled discharges (13.56 and 27.12 MHz) in Ar/NH 3 and oxygen-containing gas mixtures. A direct functionalization by nitrogen groups was not possible but 1–3 percentage of carbon–oxygen bonds increased with the total oxygen content on the expenses of sp 2 C almost independently on the plasma conditions. The plasma modified CNTs were used as fillers for polyurethane (PU) composites prepared by in situ polymerization. The composites were investigated by depth sensing indentation that revealed the existence of surface harder layer caused probably by different polymerization process in the bulk and at the surface that was in a contact with air. The significant improvement of the hardness and elastic modulus was observed when plasma-modified CNTs with high amount of oxygen were added to PU. It also improved the creep resistance of the PU, whereas the ability to recover from a deformation, i.e. anelastic recovery, did not change much.

In this article, we report on the low-level detection of hydrogen peroxide, a key player in the redox signaling pathway and a toxic product in the cellular system, using a colorimetric solution assay. Amine-terminated undoped nanocrystalline diamond thin films were grown on glass using a linear-antenna microwave plasma CVD process. The diamond surface consists mainly of -NH(2) termination. The aminated diamond surface was decorated with horseradish peroxidase (HRP) enzyme using carbodiimide coupling chemistry. The success of the HRP immobilization was confirmed by X-ray photoelectron spectroscopy (XPS). The enzymatic activity of immobilized HRP was determined with a colorimetric test based on the HRP-catalyzed oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sufonic acid (ABTS) in the presence of hydrogen peroxide. The surface coverage of active HRP was estimated to be Γ = 7.3 × 10(13) molecules cm(-2). The use of the functionalized diamond surface as an optical sensor for the detection of hydrogen peroxide with a detection limit of 35 nM was demonstrated.

Polyethylenes of different density, branching structure, crystallographic order, and their degradation due to electron beam were studied using elastic peak electron spectroscopy (EPES) and reflection electron energy loss spectroscopy (REELS) aided with line shape analysis by the pattern recognition (PR) method. This approach offers an algorithm of classification derived from a reference set, i.e. set of spectra recorded from standards exposed to low electron dose (about few C m−2), i.e. polyethylene (100% of C sp3 bonds) and polystyrene (75% of C sp2 bonds). Then, the obtained classifier is applied for identification of spectra recorded from polyethylenes exposed to electron beam (doses from 40 to 60 C m−2). The EPES REELS spectra are analyzed in the vicinity of electron quasi-elastic and inelastic losses. Due to electrons undergoing a quasi-elastic scattering from atoms of different atomic numbers, i.e. carbon and hydrogen, for undamaged polymers the surface hydrogen content can be evaluated. Changes due to electron irradiation in polyethylenes are indicated by decreasing content of hydrogen, increasing C sp2 content and changes in the π loss peak in the REELS spectra. Results of PR method are consistent with results obtained from the C 1s XPS spectra fitting and the width of C KLL XAES spectra (parameter D). Highest stability under electron irradiation was shown by polyethylene of largest molecular weight and most linear branching structure. Application of the PR method to EPES REELS spectra allows to distinguish different polyethylenes and quantify the C sp2 content.

We present the experimental observation of the spin Seebeck effect in e-Fe 2 − xAl xO 3 ( x = 0 and 0.3) thin films with Pt detection layer. The films with 40–70 nm thicknesses were deposited by a spin-coating method on Y:ZrO 2(100) substrates. The prepared films are highly oriented with the easy magnetic a-axis parallel to the film surface. The magnetic hysteresis loops measured for x = 0 at room temperature with the magnetic field parallel to the surface exhibit coercive fields up to 11.6 kOe, which is so far the highest value of e-Fe 2O 3 thin films. The spin Seebeck signal for x = 0 increases proportionally to the film's thickness, which means that the critical thickness corresponding to the magnon propagation length is greater than 70 nm. Al substitution enhances the spin Seebeck signal, while it reduces the coercive field. The shape and coercive field of the spin Seebeck hysteresis loops closely resemble magnetization loops for single phase samples. A difference is encountered in the case of films with a small amount (1–2 vol. %) of secondary soft ferrimagnetic phase, where their presence is revealed in the magnetization loops by a constricted shape, in contrast to the spin Seebeck loops, where no constriction is observed. The large coercive field makes doped e-Fe 2O 3 a suitable material for applications of the spin Seebeck effect without an external magnetic field.

X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy (XAES) have been used to investigate different polyethylene surfaces, i.e. low density polyethylene (PELD), high density polyethylene (PEHD) and polyethylene of ultra high molecular weight (PEUHMW). The ratio of Csp 2 /sp 3 was evaluated from (i) fitting of XPS C 1s spectra, (ii) the width of XAES C KLL spectra (parameter D) and (iii) line shape analysis by the pattern recognition (PR) method using the fuzzy k-nearest neighbors (fkNN) rule. The proposed approaches investigate: (i) the differences between various polyethylene surfaces, (ii) their surface changes and degradation due to electron irradiation under various doses and (iii) their stability under electron beam irradiation. The results of proposed approaches, i.e. C 1s fitting, C KLL width evaluation and PR line shape analysis applied to C 1s and C KLL transitions, are qualitatively consistent. The unirradiated polyethylenes indicate nearly Csp 3 hybridizations. Under an electron dose a rapid decrease of Csp 3 is observed, starting at a dose of 100 Cm −2 . The quantitative differences observed between results obtained from analyses using the C KLL and C 1s spectra, can be explained with a smaller average information depth of C KLL transition. However, quantitative discrepancies between results of various approaches using the same electron transition, i.e. C KLL or C 1s, are smaller. The surface degradation due to X-ray irradiation was negligible in comparison to electron beam irradiation. The PR method was efficient in identifying the polyethylene surfaces under various electron doses. The largest stability under an electron beam is exhibited by the PEUHMW.

The functionalization of multi-walled CNTs in O2/Ar and H2O/Ar low pressure capacitive discharges was studied by XPS and FT-IR. The pristine and functionalized CNTs were used as fillers in polyurethane paints. Successful plasma functionalization was confirmed by changes in atomic composition and chemical shift of XPS atomic signals. The functionalization was indicated also by the shift of IR absorption peaks corresponding to the motion of carbon skeleton, especially the peak at about 1560cm-1. The presence of carbonyl was confirmed by IR absorption peak at 1723cm-1 only for O2/Ar plasma. The plasma functionalized CNTs increased significantly the universal and plastic hardness of the CNTs reinforced polyurethane as compared to the composites with pristine CNTs.

The inelastic mean free paths (IMFPs) of electrons at a poly[methyl(phenyl)silylene] thin film surface were determined using elastic peak electron spectroscopy (EPES) and Monte Carlo calculations for a wide electron energy range, 200–1600 eV. We considered the surface composition determined from X-ray induced photoelectron spectra (XPS), the hydrogen concentration evaluated by EPES, and a correction for surface excitations. The results compare well to those calculated from the predictive TPP-2M and G1, formulae. Calculations carried out with the quantitative structure–property relationship of Cumpson and the formula of Ashley and Williams provide larger IMFP values, and can be useful only for a rough estimation.

We show correlation of microscopic surface quality and morphology of nanocrystalline diamond films as a function of deposition temperature and post-growth acid treatment detected by atomic force microscopy in phase detection regime, X-ray photoelectron spectroscopy, X-ray induced Auger electron spectroscopy, Scanning Electron Microscopy, Raman spectroscopy, and the electrical conductivity of H-terminated diamond surfaces. The correlation reflects the decrease in sp 2 amount and enhanced surface conductivity of the diamond surface after the chemical treatment. These results indicate that the AFM phase can detect clearly and microscopically carbon sp 2 phase on facets and grain boundaries of nanocrystalline diamond films.

The elastic peak electron spectroscopy (EPES) combined with the electron single scattering model calculations is applied for detecting and quantifying hydrogen at a surface region of selected polymers: polyethylenes (low, high densities and ultra high molecular weight – PELD, PEHD, PEUHMW), polypropylene – PP, polystyrene – PS, and poly[methyl(phenyl)silylene] – PMPSi. The physics under the procedure is based on an electron quasi-elastic scattering on a target atom (a recoil effect). The photoelectron C 1s and Auger electron C KLL spectra induced by Mg Kα radiation (1253.6 eV) are used for characterization of the polymer surfaces' damage produced by incident electron irradiation when applying the EPES method. The polymer surfaces irradiated with low electron dose revealed hydrogen content and C sp 2 /sp 3 ratio close to the nominal values. Ongoing electron irradiation led to the hydrogen content decrease and the C sp 2 percentage growth. The effect of surface charging on the recoil effect is also discussed.

Attenuation lengths of signal electrons are very important in surface metrology. Contrary to inelastic mean free paths (IMFP), the attenuation length is determined by both inelastic and elastic scattering events of the signal electrons in the solid. Therefore, application of attenuation lengths leads to improved accuracy in measurements of length on a nanometer scale. In the present work, photoelectron and Auger-electron spectra (AES) in regions of Au 4f, Ni 3p, Ni 2p, and Au MNN were recorded from nickel overlayers deposited in situ, step by step, on a gold surface. The experiment was coupled with advanced calculations of electron transport for the nickel/gold system. An overlayer growth mode has been elucidated by a line-shape analysis of the Ni 2p spectra with the QUASES-Tougaard software and from extensive Monte Carlo calculations of electron transport in the overlayer/substrate system with the SESSA software. The QUASES-Tougaard analysis indicated three-dimensional island growth followed by a continuous nickel overlayer for thicknesses exceeding 2 nm. The attenuation of electron intensities described by the effective attenuation length (EAL), calculated with the NIST SRD 100 database [Simulation of Electron Spectra for Surface Analysis (SESSA) software] and the NIST SRD 82 database, was found in close agreement for all electron transitions considered. The measured EAL values compared well with EALs calculated for Au 4f, Ni 3p, and Ni 2p photoelectrons, whereas the EAL derived from the measured Au MNN intensity–thickness plot was found to be about 20% less than the predicted values. Copyright © 2007 John Wiley & Sons, Ltd.

Chemically modified 5-nm detonation diamond nanoparticles (DNPs) are characterized by grazing angle reflectance (GAR) Fourier transform infrared spectroscopy (FTIR), Kelvin force microscopy (KFM), and X-ray photoelectron spectroscopy (XPS). Using GAR-FTIR we discuss the surface chemistry and stability of the as-received DNPs, and compare them with DNPs modified by annealing in air or by oxygen plasma treatment. Infrared spectra of the as-received DNPs are dominated by C–H bonds and carboxylic groups (COOH), probably related to the wet chemical treatment in acids. Annealing in air and oxygen plasma lead to a significant enhancement of C=O groups and vanishing C–H groups. After short-term (10 min) oxygen plasma treatment, infrared peaks change in intensity and position indicating a spontaneous reactivity of DNPs, probably due to the partial erosion of the graphitic shell. Prolonged oxygen plasma treatment (40 min) or annealing in air at 450 °C for 30 min provides a stable DNPs surface. Surface potentials of DNPs obtained by KFM are well correlated with the GAR-FTIR measurements. XPS characterization corroborates DNPs compositional changes after the modification procedures.

The magnitudes of the surface band bending have been determined by X-ray photoelectron spectroscopy for polar, semipolar, and non-polar surfaces of wurtzite GaN crystals. All surfaces have been prepared from crystalline GaN samples grown by the hydride-vapour phase epitaxy and separated from sapphire substrates. The Ga 3d core level peak shifts have been used for band bending determination. Small band bending magnitudes and also relatively small difference between the band bendings of the surfaces with opposite polarity have been found. These results point to the presence of electron surface states of different amounts and types on surfaces of different polarity and confirm the important role of the electron surface states in compensation of the bound surface polarity charges in wurtzite GaN crystals.

Boron-doped diamond (BDD) interfaces were chemically functionalized through the catalyst free thiol-yne reaction. Different thiolated precursors (e.g., perfluorodecanethiol, 6-(ferrocenyl)-hexanethiol, DNA) were successfully "clicked" to alkynyl-terminated BDD by irradiating the interface at 365 nm for 30 min. Thiolated oligonucleotide strands were immobilized using the optimized reaction conditions, and the surface concentration was tuned to obtain a surface coverage of 3.1 × 10(12) molecules cm(-2). Electrochemical impedance spectroscopy (EIS) was employed to follow the kinetics of hybridization and dehybridization events. The sensitivity of the oligonucleotide modified BDD interface was assayed, and a detection limit of 1 nM was obtained.

An atmospheric pressure dielectric barrier discharge burning in nitrogen with a small admixture of hexamethyldisiloxane (HMDSO) was used for the deposition of thin organosilicon films. The thin films were deposited on glass, silicon and polycarbonate substrates, and the substrate temperature during the deposition process was increased up to values within the range 25–150 °C in order to obtain hard SiO x -like thin films. The properties of the discharge were studied by means of optical emission spectroscopy and electrical measurements. The deposited films were characterized by the Rutherford backscattering and elastic recoil detection methods, x-ray photoelectron spectroscopy, infrared spectroscopy measurements, ellipsometry and the depth sensing indentation technique. It was found that the films' properties depend significantly on the substrate temperature at deposition. An increase in substrate temperature from 25 to 150 °C led to an increase in film hardness from 0.4 to 7 GPa and the film chemical composition changed from CH x Si y O z to SiO x H y . The films were transparent in the visible range.

The X-ray excited Auger electron spectroscopy (XAES), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES) methods were applied in investigating samples of nanocrystalline diamond and highly oriented pyrolytic graphite of various C sp(2)/sp(3) ratios, crystallinity conditions and grain sizes. The composition at the surface was estimated from the XPS. The C sp(2)/sp(3) ratio was evaluated from the width of the XAES first derivative C KLL spectra and from fitting of XPS C 1s spectra into components. The pattern recognition (PR) method applied for analyzing the spectra line shapes exhibited high accuracy in distinguishing different carbon materials. The PR method was found to be a potentially useful approach for identification, especially important for technological applications in fields of materials engineering and for controlling the chemical reaction products during synthesis.

We present a relatively simple method for analyzing H content on surfaces of selected commercially available polymers, i.e. polyethylene, polypropylene, polystyrene, and poly(methylphenylsilylene). The applied method, i.e. the Elastic Peak Electron Spectroscopy (EPES), is based on quasi‐elastic scattering of primary beam electrons with atoms of solid sample constituents. Electron energy, scattering angle and difference between electron mass and atomic mass of sample constituents induces an electron recoil energy loss. Recoil effect results of splitting the elastic peak into components, by their energy shifting and broadening. For above‐mentioned polymers, the EPES method indicates the surface H content close to the nominal composition. Sampling depth of the method does not exceed inelastic mean free path of electrons used in the scattering experiment. Therefore, the technique is useful to monitor H surface content during or after various surface modifications as UV, electron and ion beam modification of polymer surfaces or surface plasma treatments. Limitations of the technique are mentioned.