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Binary ZrCu nanocomposite amorphous films are synthetized by pulsed laser deposition (PLD) under vacuum (2 x 10-3 Pa) and 10 Pa He pressure, leading to fully amorphous compact and nanogranular morphologies, respectively. Then, post-thermal annealing treatments are carried out to explore thermal stability and crystallization phenomena together with the evolution of mechanical properties. Compact films exhibit larger thermal stability with partial crystallization phenomena starting at 420 °C, still to be completed at 550 °C, while nanogranular films exhibit early-stage crystallization at 300 °C and completed at 485 °C. The microstructural differences are related to a distinct evolution of mechanical properties and residual stress, with compact TFMGs showing the highest values of Young’s modulus (157 GPa), hardness (12 GPa), strain rate sensitivity (0.096), and local residual stress (+691 MPa) upon annealing at 550 °C, while nanogranular films reach the maximum values of mechanical properties at 485 °C followed by relaxation at higher temperatures due to complete crystallization. We show that PLD in combination with post-thermal annealing can generate different families of amorphous films with varying nanoscale morphologies, resulting in tunable mechanical properties and thermal stability, which can thus be used for designing novel film configurations for different fields of application.

The nanolayered structure of a forced-assembly of two immiscible amorphous polymers, prepared by layer-multiplying coextrusion, is analyzed for the first time by means of USAXS. The experimental long spacings for the series of PMMA/PS films studied show a good correlation with the nominal periodicity values of the stacks. In addition, the long spacings, derived from a localized area in AFM, are also in good agreement with the USAXS values averaged over much larger areas. The structural variation, after thermal treatment, of two samples with nominal periodicities of 174 and 215 nm is reported. In the range RT-140 °C, the nanolayered structure is mostly well preserved as evidenced by AFM. However, the absence of USAXS maxima after annealing at temperatures included in the above range has been tentatively explained by interfacial coarsening and spinodal dewetting occurring between the forced-assembled polymer layers. Above 140 °C, the interfacially driven break-up of the layers ends up with the final disappearance of the multilayered structure. © 2010 Elsevier Ltd. All rights reserved.

Rutherford backscattering spectroscopy and ion channeling and secondary ion mass spectroscopy have been used to study the evolution of a potassium profile in amorphous silicon during solid phase epitaxial crystallisation. The potassium profile exhibits some propensity for refinement in front of the crystallising interface for the concentrations used in this experiment. Also, the potassium is partially substitutional in the crystallised layer. Preliminary studies on the influence of potassium on the rate of solid phase epitaxy (SPE) in silicon are presented. Surface amorphous films doped with potassium were crystallised and the rate of epitaxy was monitored using time resolved reflectivity. The inclusion of potassium was found to retard the rate of SPE. These results indicate that potassium doped amorphous films may be helpful in efforts to further refine present models of SPE in silicon.

In this work we study the crystallization processes of two sets of amorphous Fe80B20 films fabricated by Pulsed Laser Ablation Deposition on substrates with different nature, Corning glass® and MgO(001). We analyze their magnetic hysteresis mechanisms by means of magneto-optic techniques and Transmission Electron Microscopy. The as-deposited amorphous films present a highly homogeneous uniaxial magnetic anisotropy with the easy axis orientation dependent on the type of substrate and much weaker than that of bulk alloys with similar composition. The onset of crystallization for the films deposited on glass and MgO appears, respectively, at temperatures 150 °C and 250 °C below that of their bulk counterparts. We study the role of the substrate in the crystallization mechanism and the resulting nanostructure of the magnetic films. While the crystallization of the MgO-deposited films proceeds in a broad front growing from the substrate to the surface, that of the glass-deposited films takes place through the nucleation and growth of isolated crystallites. We analyze the evolution of the coercivity during the crystallization of the films. It follows a similar trend for both types, remaining in values close to those of the amorphous precursors until it rises steeply at a given annealing temperature. The threshold of the steep coercivity increase of the glass-deposited films is shifted to lower temperatures with respect to the MgO ones, in spite of the higher crystallization onset temperature of the former. The coercivity mechanisms have been analyzed, correlated to the films interfacial characteristics and compared to those of bulk alloys.

The structural, magnetic and magnetoelastic properties of Fe–B–N amorphous films, sputtered from a Fe80B20 target, in a mixture of argon and nitrogen gas, are studied for different nitrogen partial pressures. Nitrogen incorporates into the film preserving the amorphous structure, and modifying magnetic properties. The amount of nitrogen that incorporates into the amorphous structure is found to scale linearly with the nitrogen partial pressure during film growth. The structure, magnetization, field evolution, magnetic anisotropy and magnetostrictive behaviour are determined for films with different nitrogen content. An 20% increase of both the saturation magnetization and the magnetostriction constant values is found for moderate (8%) nitrogen content when compared to those for pure Fe80B20 amorphous films. These improved properties, together with the still low coercivity of the amorphous films offer great potential for their use in magnetostrictive micro and nano magneto mechanical actuator devices.

Titanium dioxide thin films were deposited by the reactive ion-assisted sputtering method from titanium targets at various partial pressures and deposition parameters. The films were deposited onto substrates at temperatures ranging from room-temperature conditions to 722 K. A selection of thin films was post-deposited annealed at temperatures up to 972 K for 10 min and characterized by micro-Raman spectroscopy and scanning electron microscopy (SEM) and subsequently analysed to assess their photocatalytic activity. Micro-Raman characterization revealed that the as-deposited films had either predominant amorphous, rutile-like structures, anatase-like structures or anatase-rutile mixed structures. The thin films deposited with a high substrate temperature and with energy assistance from the ion source tended to be amorphous, while films deposited on a hot substrate without ion energy assistance tended to have a mixed crystalline phase. On subsequent annealing the amorphous films changed to a rutile structure at temperatures above 672 K, while mixed anatase-rutile films changed to predominant rutile structures only after thermal treatments above 872 K. Thus, this study has revealed an astonishing persistence of the anatase-rutile mixed phase at very high temperatures and showed the possible existence of a key transition temperature at 672 K, where it was possible to see a transformation from amorphous or mixed phase to a rutile or dominant rutile mixed phase. Photocatalytic tests were undertaken by using a novel method consisting of observing the degradation of a film of stearic acid by the thin films under artificial UV radiation. Of the films investigated those with anatase-rutile mixed phases showed the greatest photoactivity. This work was essential in the understanding of the correlation between growth deposition conditions, phase transitions and photocatalytic activity. This set of experiments demonstrated that titania made under a highly oxidizing atmosphere, wi

Titanium dioxide thin films were deposited by the reactive ion-assisted sputtering method from titanium targets at various partial pressures and deposition parameters. The films were deposited onto substrates at temperatures ranging from room-temperature conditions to 722 K. A selection of thin films was post-deposited annealed at temperatures up to 972 K for 10 min and characterized by micro-Raman spectroscopy and scanning electron microscopy (SEM) and subsequently analysed to assess their photocatalytic activity. Micro-Raman characterization revealed that the as-deposited films had either predominant amorphous, rutile-like structures, anatase-like structures or anatase-rutile mixed structures. The thin films deposited with a high substrate temperature and with energy assistance from the ion source tended to be amorphous, while films deposited on a hot substrate without ion energy assistance tended to have a mixed crystalline phase. On subsequent annealing the amorphous films changed to a rutile structure at temperatures above 672 K, while mixed anatase-rutile films changed to predominant rutile structures only after thermal treatments above 872 K. Thus, this study has revealed an astonishing persistence of the anatase-rutile mixed phase at very high temperatures and showed the possible existence of a key transition temperature at 672 K, where it was possible to see a transformation from amorphous or mixed phase to a rutile or dominant rutile mixed phase. Photocatalytic tests were undertaken by using a novel method consisting of observing the degradation of a film of stearic acid by the thin films under artificial UV radiation. Of the films investigated those with anatase-rutile mixed phases showed the greatest photoactivity. This work was essential in the understanding of the correlation between growth deposition conditions, phase transitions and photocatalytic activity. This set of experiments demonstrated that titania made under a highly oxidizing atmosphere, wi

The behavior of YFeO3 thin-film electrodes under illumination is investigated for the first time. YFeO3 thin films on F-doped SnO2 (FTO) electrodes were prepared by two different methods (A) deposition of nanoparticles synthesized by the so-called ionic liquid route at 1000° C followed by sintering at 400° C and (B) spin coating of a sol-gel precursor followed by a heat treatment at 640° C. Method A provides highly texture films with exquisite orthorhombic phase purity and a direct band gap transition at 2.45 eV. On the other hand, method B results in very compact and amorphous films. XPS confirmed a Fe3+ oxidation state in both films, with a surface composition ratio of 70:30 Y:Fe. Both materials exhibit cathodic photocurrent responses arising from hydrogen evolution in alkaline solutions with an onset potential of 1.05 V vs. RHE. The complex behavior of the photoresponses is rationalized in terms of recombination losses, band edge energy tails and hindered transport across the oxide thin film.

BaTiO₃ (BTO) layers were deposited by pulsed laser deposition (PLD) on TiNb, Pt/TiNb, Si (100), and fused silica substrates using various deposition conditions. Polycrystalline BTO with sizes of crystallites in the range from 90 nm to 160 nm was obtained at elevated substrate temperatures of (600 °C–700 °C). With increasing deposition temperature above 700 °C the formation of unwanted rutile phase prevented the growth of perovskite ferroelectric BTO. Concurrently, with decreasing substrate temperature below 500 °C, amorphous films were formed. Post-deposition annealing of the amorphous deposits allowed obtaining perovskite BTO. Using a very thin Pt interlayer between the BTO films and TiNb substrate enabled high-temperature growth of preferentially oriented BTO. Raman spectroscopy and electrical characterization indicated polar ferroelectric behaviour of the BTO films.

The behavior of YFeO3 thin-film electrodes under illumination is investigated for the first time. YFeO3 thin films on F-doped SnO2 (FTO) electrodes were prepared by two different methods (A) deposition of nanoparticles synthesized by the so-called ionic liquid route at 1000° C followed by sintering at 400° C and (B) spin coating of a sol-gel precursor followed by a heat treatment at 640° C. Method A provides highly texture films with exquisite orthorhombic phase purity and a direct band gap transition at 2.45 eV. On the other hand, method B results in very compact and amorphous films. XPS confirmed a Fe3+ oxidation state in both films, with a surface composition ratio of 70:30 Y:Fe. Both materials exhibit cathodic photocurrent responses arising from hydrogen evolution in alkaline solutions with an onset potential of 1.05 V vs. RHE. The complex behavior of the photoresponses is rationalized in terms of recombination losses, band edge energy tails and hindered transport across the oxide thin film.

Here we report on preparation of Eu3+-doped Gd(2)Ti(2)O(7)pyrochlore luminescent thin films by pulsed laser deposition technique and their structural, morphological and optical characterization. The influence of annealing temperature and background gas (air vs. argon) on film photoluminescence is examined fort he optimization of post-deposition annealing conditions. As-deposited amorphous films become pure pyrochlore crystalline after calcination at temperatures higher than 1000 degrees C. Atomic force microscopy showed increase in the grain size from similar to 20 nm in the as-deposited to similar to 60 nm in the crystalline sample annealed at 1100 degrees C. Scanning electron microscopy showed dense films with the uniform thickness of about 700 nm. Luminescence spectra of crystalline films were complex and composed of better resolved emission lines than in the amorphous sample. Emission spectra showed that symmetry of Eu3+ sites become disturbed in annealed films due to the extrinsic thermal stress. Films treated in argon displayed similar emission and excitation spectral features like air-treated ones, but with better resolved emissionlines. Calculated quantum efficiency of emission showed that optimization of annealing conditions led to an enhancement of films luminescence. The highest quantum efficiency of emission and the longestlife time is found for the sample annealed at 1100 degrees C in presence of argon. Crown Copyright (C) 2015 Published by Elsevier B. V. All rights reserved.

Here we report on preparation of Eu3+-doped Gd(2)Ti(2)O(7)pyrochlore luminescent thin films by pulsed laser deposition technique and their structural, morphological and optical characterization. The influence of annealing temperature and background gas (air vs. argon) on film photoluminescence is examined fort he optimization of post-deposition annealing conditions. As-deposited amorphous films become pure pyrochlore crystalline after calcination at temperatures higher than 1000 degrees C. Atomic force microscopy showed increase in the grain size from similar to 20 nm in the as-deposited to similar to 60 nm in the crystalline sample annealed at 1100 degrees C. Scanning electron microscopy showed dense films with the uniform thickness of about 700 nm. Luminescence spectra of crystalline films were complex and composed of better resolved emission lines than in the amorphous sample. Emission spectra showed that symmetry of Eu3+ sites become disturbed in annealed films due to the extrinsic thermal stress. Films treated in argon displayed similar emission and excitation spectral features like air-treated ones, but with better resolved emissionlines. Calculated quantum efficiency of emission showed that optimization of annealing conditions led to an enhancement of films luminescence. The highest quantum efficiency of emission and the longestlife time is found for the sample annealed at 1100 degrees C in presence of argon. Crown Copyright (C) 2015 Published by Elsevier B. V. All rights reserved.

Two series of Nb–Si–C thin films of different composition have been deposited using DC magnetron sputtering. In the first series the carbon content was kept at about 55 at.% while the Si/Nb ratio was varied and in the second series the C/Nb ratio was varied instead while the Si content was kept at about 45 at.%. The microstructure is strongly dependent on Si content and Nb–Si–C films containing more than 25 at.% Si exhibit an amorphous structure as determined by X-ray diffraction. Transmission electron microscopy, however, induces crystallisation during analysis, thus obstructing a more detailed analysis of the amorphous structure. X-ray photo-electron spectroscopy suggests that the amorphous films consist of a mixture of chemical bonds such as Nb–Si, Nb–C, and Si–C. The addition of Si results in a hardness decrease from 22 GPa for the binary Nb–C film to 18 – 19 GPa for the Si-containing films, while film resistivity increases from 211 μΩcm to 3215 μΩcm. Comparison with recently published results on DC magnetron sputtered Zr–Si–C films, deposited in the same system using the same Ar-plasma pressure, bias, and a slightly lower substrate temperature (300 °C instead of 350 °C), shows that hardness is primarily dependent on the amount of Si–C bonds rather than type of transition metal. The reduced elastic modulus on the other hand shows a dependency on the type of transition metal for the films. These trends for the mechanical properties suggest that high wear resistant (high H/E and H3/E2 ratio) Me–Si–C films can be achieved by appropriate choice of film composition and transition metal., Funding Agencies|Vinnova (Swedish Governmental Agency for Innovation Systems) through the VINN Excellence Centre FunMat||Swedish Research Council (VR)

Two series of Nb–Si–C thin films of different composition have been deposited using DC magnetron sputtering. In the first series the carbon content was kept at about 55 at.% while the Si/Nb ratio was varied and in the second series the C/Nb ratio was varied instead while the Si content was kept at about 45 at.%. The microstructure is strongly dependent on Si content and Nb–Si–C films containing more than 25 at.% Si exhibit an amorphous structure as determined by X-ray diffraction. Transmission electron microscopy, however, induces crystallisation during analysis, thus obstructing a more detailed analysis of the amorphous structure. X-ray photo-electron spectroscopy suggests that the amorphous films consist of a mixture of chemical bonds such as Nb–Si, Nb–C, and Si–C. The addition of Si results in a hardness decrease from 22 GPa for the binary Nb–C film to 18 – 19 GPa for the Si-containing films, while film resistivity increases from 211 μΩcm to 3215 μΩcm. Comparison with recently published results on DC magnetron sputtered Zr–Si–C films, deposited in the same system using the same Ar-plasma pressure, bias, and a slightly lower substrate temperature (300 °C instead of 350 °C), shows that hardness is primarily dependent on the amount of Si–C bonds rather than type of transition metal. The reduced elastic modulus on the other hand shows a dependency on the type of transition metal for the films. These trends for the mechanical properties suggest that high wear resistant (high H/E and H3/E2 ratio) Me–Si–C films can be achieved by appropriate choice of film composition and transition metal., Funding Agencies|Vinnova (Swedish Governmental Agency for Innovation Systems) through the VINN Excellence Centre FunMat||Swedish Research Council (VR)

Two series of Nb–Si–C thin films of different composition have been deposited using DC magnetron sputtering. In the first series the carbon content was kept at about 55 at.% while the Si/Nb ratio was varied and in the second series the C/Nb ratio was varied instead while the Si content was kept at about 45 at.%. The microstructure is strongly dependent on Si content and Nb–Si–C films containing more than 25 at.% Si exhibit an amorphous structure as determined by X-ray diffraction. Transmission electron microscopy, however, induces crystallisation during analysis, thus obstructing a more detailed analysis of the amorphous structure. X-ray photo-electron spectroscopy suggests that the amorphous films consist of a mixture of chemical bonds such as Nb–Si, Nb–C, and Si–C. The addition of Si results in a hardness decrease from 22 GPa for the binary Nb–C film to 18 – 19 GPa for the Si-containing films, while film resistivity increases from 211 μΩcm to 3215 μΩcm. Comparison with recently published results on DC magnetron sputtered Zr–Si–C films, deposited in the same system using the same Ar-plasma pressure, bias, and a slightly lower substrate temperature (300 °C instead of 350 °C), shows that hardness is primarily dependent on the amount of Si–C bonds rather than type of transition metal. The reduced elastic modulus on the other hand shows a dependency on the type of transition metal for the films. These trends for the mechanical properties suggest that high wear resistant (high H/E and H3/E2 ratio) Me–Si–C films can be achieved by appropriate choice of film composition and transition metal., Funding Agencies|Vinnova (Swedish Governmental Agency for Innovation Systems) through the VINN Excellence Centre FunMat||Swedish Research Council (VR)

Two series of Nb–Si–C thin films of different composition have been deposited using DC magnetron sputtering. In the first series the carbon content was kept at about 55 at.% while the Si/Nb ratio was varied and in the second series the C/Nb ratio was varied instead while the Si content was kept at about 45 at.%. The microstructure is strongly dependent on Si content and Nb–Si–C films containing more than 25 at.% Si exhibit an amorphous structure as determined by X-ray diffraction. Transmission electron microscopy, however, induces crystallisation during analysis, thus obstructing a more detailed analysis of the amorphous structure. X-ray photo-electron spectroscopy suggests that the amorphous films consist of a mixture of chemical bonds such as Nb–Si, Nb–C, and Si–C. The addition of Si results in a hardness decrease from 22 GPa for the binary Nb–C film to 18 – 19 GPa for the Si-containing films, while film resistivity increases from 211 μΩcm to 3215 μΩcm. Comparison with recently published results on DC magnetron sputtered Zr–Si–C films, deposited in the same system using the same Ar-plasma pressure, bias, and a slightly lower substrate temperature (300 °C instead of 350 °C), shows that hardness is primarily dependent on the amount of Si–C bonds rather than type of transition metal. The reduced elastic modulus on the other hand shows a dependency on the type of transition metal for the films. These trends for the mechanical properties suggest that high wear resistant (high H/E and H3/E2 ratio) Me–Si–C films can be achieved by appropriate choice of film composition and transition metal., Funding Agencies|Vinnova (Swedish Governmental Agency for Innovation Systems) through the VINN Excellence Centre FunMat||Swedish Research Council (VR)

TiO2 thin films were deposited on silicon wafer substrates by low-field (1

An experimental program has been conducted to determine the effect of phosphorus on the corrosion and passivation behavior of Fe---Cr---P alloys. Chemically homogeneous 60 nm films of Fe---10Cr---xP (x from 0 to 35 at.%) were prepared by multilayer evaporation followed by ion beam mixing with Kr+ ions. Films with a phosphorus content of at least 25 at.% were found to be entirely amorphous, while films with 15 at.% P consisted of both amorphous and bcc phases. Recrystallization of the amorphous phase was accomplished by heating the samples to 450[deg]C in a purified argon flow furnace. Electrochemical polarization tests in an acid solution have shown the Fe---10Cr---xP films to be more corrosion resistant than Fe---10Cr, with the corrosion resistance increasing with the amount of P present. The corrosion resistance is not significantly affected when the amorphous films are recrystallized, indicating that the behavior is chemically controlled and not a result of the amorphous structure. When examined by XPS, the phosphorus appears to enhance passivation by encouraging Cr enrichment in the oxide and by incorporating in the oxide as phosphate.

Two series of aromatic poly(amide-benzoxazole)s have been obtained from 5-chlorocarbonyl-2-(4-chlorocarbonylphenyl)benzoxazole (NBOC) and 6-chlorocarbonyl-2-(4-chlorocarbonylphenyl)benzoxazole (OBOC). NBOC and OBOC were synthesized by a three-step process with high yields, and they were reacted with aromatic diamines by using the in situ silylation method which yielded polymers of high inherent viscosities. The solubility of these polymers was similar to that of aromatic polyamides, being soluble in aprotic polar solvents. All polymers could be processed to tough, creasable amorphous films with good mechanical properties, the values of tensile strength ranging from 92 to 113 MPa with moduli above 2 GPa. The glass transition temperatures were above 300°C, whilst the onset of thermal degradation ranged from 455 to 515°C. A theoretical study was also done, by means of computational chemistry methods, to relate the orientation of the benzoxazole ring in both series with monomer reactivity and polymer properties.

The ion-beam-induced chemical vapor deposition (IBICVD) method has been used for the preparation of TiO2, Al2O3 and mixed oxide AlnTimOx amorphous films on silica substrates. Also, a double-layer Al2O3/TiO2 film has been prepared. The reflectivity (low angle X-ray diffraction) technique, together with transmission electron microscopy (TEM) and UV-Vis absorption spectroscopy, have been used to get information about thickness, roughness and electronic density of the films. It has been found that the films are homogeneous and flat being the Al2O3 layers less dense than the TiO2 layers. In particular, AlnTimOx films can be prepared with variable composition and refraction index. The values obtained for electronic density by X-ray reflectivity have been correlated with the compaction degree of the films as stated from TEM and UV-Vis absorption spectroscopy studies.

Relaxed amorphous areas induced in SbxGe1-x. films by laser irradiation have been crystallised by isothermal annealing during in-situ observation in a transmission electron microscope. The results show that the nucleation process and the temperatures required to trigger the crystallisation are different for films with compositions on either side of the eutectic (x = 0.85). The results suggest that relaxation only leads to a substantial decrease of the free energy in amorphous films with a Sb content higher than that of the eutectic.

The crystallization kinetics in SbxSe100-x films with 39≤x≤58 is studied by monitoring the optical transmission of the films during both isothermal and constant rate heatings. The structure of the films upon crystallization and at certain intermediate stages is studied by electron microscopy techniques. The results are analyzed in the frame of the Johnson-Mehl-Avrami theory in order to determine the kinetic parameters (Avrami exponent, activation energy and frequency factor) in addition to the crystallization temperature. The results show that film crystallization is always preceeded by a relaxation process which modifies substantially the optical properties of the amorphous material. Amorphous films with compositions close to the stoichiometric compound (Sb2Se3) are found to show the highest activation energy for crystallization.

Crystallization is triggered in Sb-rich GeSb and SbO amorphous films by irradiation with short (nanosecond) and ultrashort (picosecond) laser pulses. Crystallization is accompanied by optical contrast and the process ends within the nanosecond time scale, independently of the irradiation pulse length (nano- or picosecond). In GeSb alloys the observed process always involves melting and rapid solidification. The observed changes in the film optical properties both during and after laser irradiation are consistent with the formation of Sb crystals with no evidence of other crystalline phases. © 1993.

We report metastable phase formation in germanium-rich Ge1-xAlx amorphous films (x = 0.35 and 0.24) induced by laser melting. The results show that the nucleation phase for solidification is germanium and that germanium faceted crystals and dendrites are formed. The four known metastable crystalline phases of GeAl are observed and compared with those obtained by other rapid solidification techniques. For the range of compositions in the present study, the hexagonal phase is found to nucleate the rhombohedral phase and it is the first time that the orthorhombic phase is found as a consequence of a melting-solidification process. © 1990.

Rapidly-solidified microcrystalline alloys typically possess a fine-grained matrix with solute distributed in a cellular arrangement, either in the form of enriched cell-wall regions or as second-phase particles at the original cell walls. It is unclear whether optimal strength would be achieved when a second phase is distributed as discrete particles or as a continuous film. The microstructures and mechanical properties of a series of CuSiB alloys were examined both at room temperature and at high temperature. Depending on the alloy considered, fairly stable amorphous films, or discrete particles, arranged in a cell structure, are formed by rapid solidification. The continuous second-phase film is shown to lead to higher average internal stresses and material deformation process, during hot testing, appears to be the same as that controlling deformation in the particle-strengthened materials

The task of differentiating very small metal aggregates supported on amorphous films from the phase contrast image features inherently stemming from the support is extremely difficult in the nanometer particle size range. Digital image processing was employed to overcome some of the ambiguities in evaluating such micrographs. The processing steps included: (a) shading correction and contrast enhancement by adaptive filtering, (b) noise reduction by median filtering, and (c) noise cleaning by adaptive filtering and thresholding. It was demonstrated that such processing allowed positive particle detection and a limited degree of statistical size analysis even for micrographs where by bare eye examination the distribution between particles and erroneous substrate features would seem highly ambiguous. The smallest size class detected for Pd/C samples peaks at 0.8 nm. We found this size class in various samples prepared under different evaporation conditions and conclude that these particles consist of >a magic number> of 13 atoms and have cubo-octahedral or icosahedral crystal structure. © 1988.

Ge 2Sb 2Te 5 films were locally crystallized by a tightly focused laser beam and the structural evolution was studied by Raman scatting. The marks recorded by a broad range of laser power were studied by optical microscope. Raman spectra of films with irradiation power of 0.1 mW and 1 mW were consistent with those of films annealed at 140°C and 400°C, respectively. It reveals that both the cubic and hexagonal crystalline phases have been achieved under the irradiation of 488 nm laser in amorphous Ge 2Sb 2Te 5 films. Specifically, the appearance of a new band of ∼141 cm -1 in films with irradiation power larger than 1.25 mW confirms that the over-irradiation causes the segregation of Te crystalline phase in films.

Energetic deposition of high speed steel (HSS) films has been performed using a filtered cathodic vacuum arc system fitted with a AISI M2 HSS cathode. The mechanical properties and microstructure of the films were investigated as a function of the deposition energy. The stoichiometry and microstructure of the deposited films were different to that of the cathode and a dependence on the deposition energy was found. Films deposited at low deposition energies (<100 eV) exhibited reduced concentrations of Mo and W and a smaller average crystallite size than the M2 HSS cathode. These films were found to be significantly harder than the M2 HSS cathode, possibly due to their smaller average crystallite size. A HSS film consisting of an amorphous phase with isolated crystals of bcc Fe was produced using high deposition energy and the deposition rate was found to decrease, likely due to sputtering.

The erosion by 30 and 200 eV/D at temperatures between 300 and 1100 K was investigated for magnetron-sputtered films, consisting of carbon and metal (2–7 at.% W, Ti, Zr) present as nanometer-sized carbide crystallites. The total erosion yield was determined from weight-loss measurements and film thickness changes measured by RBS. The chemical erosion yield was obtained from the CD4 signal of mass spectrometry. The total erosion yield of doped films is reduced by a factor of 3–20 compared to pure C films. The CD4 production yield decreases less implying that the distribution of the chemically eroded species was changed by the dopants. Therefore, measuring only CD4 production or its spectroscopic signature could yield to misleading values and interpretations.

Ultra-high-dose Si ion implantation (1×1018 cm-2) into both amorphous and crystalline Si has been studied as a function of implantation temperature from liquid nitrogen to 250°C. The samples were analysed before and after 600°C annealing by Rutherford