Showing papers in "Thin Solid Films in 1981"
TL;DR: In this paper, the mechanism of formation of plasma-sprayed coatings was examined and related to the microstructure produced, and it was shown that the real area of contact between individual lamellae within the coating and between lamella and substrate is much less than the apparent area because of adsorbed and entrapped gas, oxide films or other contamination.
Abstract: The mechanism of formation of plasma-sprayed coatings was examined and related to the microstructure produced. The evidence suggests that the real area of contact between individual lamellae within the coating and between lamellae and substrate is much less than the apparent area because of adsorbed and entrapped gas, oxide films or other contamination. The measured fracture toughness parameters for cohesive failure of coatings are generally much lower than would be expected for complete wetting of previously solidified material by impinging droplets, reflecting the imperfect contact between lamellae. Similar considerations apply to the lamellae-substrate interface at which the contact angle would generally be greater than for lamellae-lamellae interfaces. The difference between the fracture toughness values for ceramic and metallic coatings and the role of a metallic subcoat under ceramic coatings can be explained in terms of plastic deformation of metallic lamellae. The very high adhesive fracture toughness of Ni Al coatings on steel implies more effective contact rather than inherently stronger bonding between contact points. This may be due to aluminothermic reduction of the oxide film on steel. Improvement of the mechanical properties of plasma-sprayed coatings requires methods for increasing the real area of contact between lamellae and between lamellae and substrate.
367 citations
TL;DR: In this article, the electromigration resistance of Al-0.5%Cu meander lines was found to increase with increasing grain size s and degree of {111} preferred orientation and with decreasing spread σ in the grain size distribution.
Abstract: The electromigration resistance of Al-0.5%Cu meander lines was found to increase with increasing grain size s and degree of {111} preferred orientation and with decreasing spread σ in the grain size distribution. This dependence on microstructure can be expressed in terms of the empirical quantity ( s σ 2 ) log ( I 111 I 200 ) 3 which correlates well with the electromigration lifetime of films obtained by different deposition techniques.
328 citations
TL;DR: In this paper, the optical and physical properties of various single films and multilayer systems are described and their history, the dip-coating procedure and especially the chemical processes are described.
Abstract: Substrates, particularly large panes of glass, are withdrawn from organometallic solutions into a humid atmosphere. Evaporation of the solvent, hydrolysis of the organometallic compounds and polycondensation take place until the oxidic state is reached. The optical and physical properties of various single films and multilayer systems are described. Their history, the dip-coating procedure and especially the chemical processes are described. Single oxide layers and crystalline and amorphous multicomponent oxide layers such as, for instance, glasses and multilayer systems can be fabricated.
229 citations
TL;DR: In this article, the dependence of the deposition rates on the deposition parameters is presented and a hysteresis phenomenon is described, showing that the layers can be made soft for low bias voltages and high ethylene pressures and very hard for the remaining parameter space.
Abstract: i-Carbon was deposited onto various substrates using an r.f. glow discharge in ethylene at pressures in the range 0.5–130 m Torr and bias voltages of 10–1300 V. The dependence of the deposition rates on the deposition parameters is presented. The dependence of the coefficient of sliding friction on the relative humidity is given and a hysteresis phenomenon is described. Microhardness measurements show that the layers can be made soft for low bias voltages and high ethylene pressures and very hard for the remaining parameter space. Endurance measurements show a marked dependence of the total number of revolutions on the normal load. i-Carbon layers exhibit a high compressive stress which is strongly dependent on the deposition parameters.
227 citations
TL;DR: In this paper, the free electron densities of up to 1021 cm−3 and mobilities in the range 10−70 cm2 V−1s−1 can be obtained by means of an appropriate doping and/or oxygen deficit.
Abstract: Thin films of doped SnO2 and In2O3 are used as transparent heat reflectors. Free electron densities of up to 1021 cm−3 and mobilities in the range 10–70 cm2 V−1s−1 can be obtained by means of an appropriate doping and/or oxygen deficit. Tin, acting as an electron donor, is soluble in In2O3 up to 6 at.%. After an oxidizing heat treatment the electrons of the donors are extensively trapped and the mobility of the remaining electrons is decreased. The cut-off wavelength between the transparent and reflecting spectral regions can be adjusted by the plasma wavelength of the free electrons, i.e. by the electron density. The filter losses due to visiblw absorption and incomplete IR reflection are discussed and these demonstrate the importance of a high free electron mobility. The influence of the surface resistance and the angle of observation on the thermal emissivity was measured. Some examples of the application and specific optimization of In2O3 thin films, which are produced by spray pyrolysis, are presented.
214 citations
TL;DR: In this article, a sliding friction test run at a normal load of 63.4 kgf and a speed representing 800 load applications per minute was performed on sputtered MoS2 films.
Abstract: Sputtered MoS2 films providing satisfactory lubricating properties can be achieved by proper control of processing parameters. The sputtering process is ideally suited to applications which require very thin films of MoS2 as it yields coatings with excellent substrate adhesion and which have endurances per unit thickness in excess of those of conventional dry film coatings. Sputtered interfacial coatings of other materials can be deposited onto certain substrates to enhance lubricating qualities and adherence. In the work presented here, the evaluation method was a sliding friction test run at a normal load of 63.4 kgf and a speed representing 800 load applications per minute. With this set of test parameters sputtered MoS2 films produced under widely reported process parameters manifest irregular coefficients of friction and variability of endurance. The films also exhibit time-related changes in their coefficients of friction which stabilize from 6 to 12 h after sputtering. The observed irregularities are not peculiar to any particular method of sputtering and are most probably caused by residual stresses or inhomogeneous crystal growth as the film increases in thickness. The observed frictional instabilities and irregularities can be eliminated or greatly reduced by the codeposition of certain metals with MoS2. These metal additives appear to increase the size of the acicular crystallites by approximately 35%, and in appropriate concentrations they provide synergistic effects such as a lowering of the coefficient of friction and an increase in the endurance per unit thickness. The ability to vary the ratio of metals to MoS2 enables films to be produced which are controllably harder than those obtained with MoS2 alone. Up to about 10% the metal additives do not adversely affect the lubricating qualities. The codeposited films have stable coefficients of friction with increased endurance per unit thickness and are clearly superior to standard sputtered MoS2 films.
214 citations
TL;DR: The Pyrosol process, based on the pyrolysis of an aerosol produced by ultrasonic spraying, is a method of choice for depositing thin coatings on glass as mentioned in this paper.
Abstract: The Pyrosol process, based on the pyrolysis of an aerosol produced by ultrasonic spraying, is a method of choice for depositing thin coatings on glass. The deposition of metallic oxides (In2O3, SnO2, Fe2O3 etc.) is at present the main application of this process but it is also possible to deposit other materials such as sulphides. In the special case of transparent conductive oxides, resistivities of about 2.2×10−4 ohms cm are obtained for indium oxide doped with tin oxide, and of about 0.7×10−3 ohms cm for tin oxide doped with fluorine. For a coating approximately 6000 A thick the transmission of light for λ=0.4–0.7 microm is 88% for In2O3 (e=0.12) and 85% for SnO2 (e=0.2). The main advantages of this method of chemical vapour deposition are its ease of operation, its low cost and the quality of the coatings obtained as a result of the homogeneity of the droplet size distribution. Thin layers deposited in this way are used in optics, electronics, decoration and solar energy conversion.
213 citations
TL;DR: The synthesis of TiN by physical vapour deposition at temperatures below 500°C allows high speed steel to be coated after the final machining operation as mentioned in this paper, which can be used for watch cases and wrist bracelets where its abrasion resistance is far better than that of the standard 20 μm gold plaque.
Abstract: The synthesis of TiN by physical vapour deposition at temperatures below 500°C allows high speed steel to be coated after the final machining operation. The Vickers hardness and the density of the hard coatings are nearly the same as those in bulk form. The surface roughness of the coating is, to a large extent, identical with that of the uncoated substrate. Excellent adhesion of the deposited coating is achieved. An important field of application is cutting tools, e.g. twist drills. The coated drills show a marked improvement in service life and yield a drilled hole with a higher surface quality. Remarkable improvements in service life have also resulted from the use of TiN-coated forming tools such as deep-drawing tools. The gold-coloured TiN coating can be produced in approximately the same colour nuances as the standardized gold alloys of the watch industry. Consequently, it can be used for watch cases and wrist bracelets where its abrasion resistance is far better than that of the highest industrial standard 20 μm gold plaque.
204 citations
TL;DR: In this paper, the basic physical, electrical and optical properties of thin films of doped indium oxide (In2O3) or of tin oxide (SnO2) are reviewed in relation to the dopant concentrations and stoichiometric deviations.
Abstract: Thin films of doped indium oxide (In2O3) or of tin oxide (SnO2), as well as mixed compounds of the two (indium tin oxide (ITO)), can be prepared in a highly conductive form with the important property of being highly transparent in the visible and near-IR regions of the solar spectrum. Moreover, these layers are physically and chemically resistant and adhere well to many substrates. Potential applications are numerous: specifically as coatings for heat mirror systems as well as in solar cell technology. The “spraying” method of preparation uses a hydrolysis reaction at relatively low temperatures (400–600 °C) in an alcoholic solution of tin or indium chloride. The basic physical, electrical and optical properties of the films are reviewed in relation to the dopant concentrations and stoichiometric deviations. (Typical parameters for ITO are resistivity ϱ≈5×10−4 ohms cm, transmission coefficient T≈80–90% in the wavelength range 0.3–1.5 microm and sheet resistance R□≈10 ohms.) In recent years the economic contingencies related to the energy crisis have led to an increase of interest in these layers, but the marked rise in the number of publications does not correspond to concomitant improvements in layer quality or to a better understanding of the properties. Some basic theoretical limitations can be pointed out: electron-hole pair creation limits transparency at short wavelengths and the steep increase of reflectivity due to free carrier absorption limits it at long wavelengths. The latter factor is directly related to the electrical conductivity. A fundamental conflict between transparency and conductivity is therefore built in. The properties of these layers are compared with those of chemically identical layers prepared by different methods, as well as with those of some other transparent and conducting films of quite different compositions.
185 citations
TL;DR: In this article, an analysis is presented of published sets of pure element sputtering yields with the objective of predicting data for elements for which measurements are not available, and it is shown that these data sets each correlate with Sigmund's target dependence predictions with a scatter of 20%.
Abstract: An analysis is presented of published sets of pure element sputtering yields with the objective of predicting data for elements for which measurements are not available. First the target dependence of the sputtering yield for 500 eV argon ions, as measured by Wehner, is related to the target dependence predicted by Sigmund's theory for low energies. This ratio shows that the measurements are progressively reduced as the target's reactivity with oxygen increases. This relationship allows Wehner's data to be “corrected” for contamination, after which the standard deviation of the scatter about Sigmund's target dependence is reduced from 37% to 20%. A similar analysis for Oechsner's more recent compilation shows weaker contamination effects. The “corrected” data of Wehner and Oechsner correlate with each other with a scatter of only 10%, indicating the veracity of these “corrected” data sets. These data sets each correlate with Sigmund's target dependence predictions with a scatter of 20%—thus the sets may be extended in this way to all elements with similar accuracy.
151 citations
TL;DR: In this paper, the currentvoltage characteristics of metal/Se-Point contact structures (M/SeP) with electrodes of different metals (aluminium, gold, chromium, copper, silver and tungsten) were studied systematically.
Abstract: The current-voltage ( I-V ) characteristics of metal/Se-point contact structures (M/Se-P) with electrodes of different metals (aluminium, gold, chromium, copper, silver and tungsten) were studied systematically. A stable polarized memory switching effect was obtained with the Al/Se-P Cu devices. The threshold voltage V s was independent of the selenium thickness. The memorized ON state disappeared progressively when the applied voltage was removed or when a reverse voltage was applied. The I-V characteristics were not disturbed by annealing (crystallization) of the selenium but they showed aging effects. The switching operations obtained with other electrode materials were not reproducible. In the case of the aluminium electrode this can be explained by the growth of an Al 2 O 3 layer between the aluminium and the selenium.
TL;DR: In this paper, the authors attempted to optimize the transmission and resistivity of thin films 10 cm × 10 cm in area, and the design of the system used is such that it is possible to control all the parameters affecting the formation of these layers.
Abstract: In the study presented in this paper we attempted to optimize the transmission and resistivity of thin films 10 cm × 10 cm in area. The design of the system used is such that it is possible to control all the parameters affecting the formation of these layers. The nozzle moves above the substrate which is heated to a high temperature. The solution is pulverized by means of a neutral gas ( e.g. nitrogen) sothat it arrives at the substrate in the form of very fine drops. The layer thickness is monitored by observing the interference orders in the thin films, and so we can modify various parameters such as the speed of the solution, the dopant concentration and the substrate temperature whilst ensuring that the thickness is held constant.
TL;DR: In this paper, the authors review the chemical, mechanical and thermal properties of polyimides and highlight the importance of adhesion to the substrate in order to retard the metal lead corrosion that occurs at high temperatures and under conditions of moisture.
Abstract: Polyimide films are reliable high temperature planarizing insulators for multilevel interconnection systems, which may be the key to high yielding bipolar and MOS very large-scale integrated circuits. In this paper we review the chemical, mechanical and thermal properties of polyimides. The important process steps are traced: planarization by coating, adhesion and patterning both by photoresist masking and by photosensitization of the polymide film. Reliability discussions include the influence of sodium ions on h FE at high temperatures and the effect of water contamination of the starting copolymers on the high temperature stability of the final cured resin. Emphasis is placed on the importance of polyimide adhesion to the substrate in order to retard the metal lead corrosion that occurs at high temperatures and under conditions of moisture. Methods to deal with the higher conductivity of polyimide relative to that of ceramic insulators are summarized.
TL;DR: In this article, the average internal stress measured by the cantilever method was 5 x 108N m−2 compression, and the dependence of the size of the wrinkles on the film thickness was deduced and compared with experimental results.
Abstract: The mechanical properties of carbon films 500–3000 A thick deposited onto glass substrates were investigated. The average internal stress measured by the cantilever method was 5 x 108N m−2 compression. This large stress often generates wrinkles in the films. Young's modulus of the film and the adhesion energy between the film and the substrate can be estimated from the shape and size of the wrinkles. As a method of estimation, the elastic energy of the wrinkled film is considered. The dependence of the size of the wrinkles on the film thickness is deduced and compared with experimental results.
TL;DR: In this article, the low temperature chemical vapour deposition (CVD) of TiC, TiN and TiCxN1−x in the presence of a d.c. plasma is described.
Abstract: The low temperature chemical vapour deposition (CVD) of TiC, TiN and TiCxN1−x in the presence of a d.c. plasma is described. The deposition rates were independent of the substrate temperature, but the substrate temperature had a marked effect on the coating properties. Coatings obtained at temperatures in excess of 400°C for TiN and 500°C for TiC began to show properties similar to those of coatings obtained by conventional CVD.
TL;DR: A commercially available scratch tester was used to study the response of test samples of a cold work steel, coated with TiC or TiN by chemical vapour deposition, to the scratch test as discussed by the authors.
Abstract: A commercially available scratch tester was used to study the response of test samples of a cold work steel, coated with TiC or TiN by chemical vapour deposition, to the scratch test. The results confirm that the loss of the coating does not occur in a simple way. The initial stage is a loss of local coating cohesion with a local loss of adhesion occuring at somewhat higher loads. The load-bearing capacity of the coating is lost rapidly at this stage and this is followed by chipping at the edge of the channel and then by partial (TiC) or total (TiN) massive loss of adhesion. In the samples studied the onset of cohesive and adhesive loss is accompanied by increasing amounts of acoustic emission. The results seem to indicate that the scratch test is able to determine the limit of the load-bearing capacity of a coating. This limit is determined by comparing the stylus load, the microhardness in the scratch channel, the acoustic emission and the microscopic appearance of the scratches.
TL;DR: In this paper, room temperature interdiffusion studies of Au/Sn thin film couples were made using transmission electron microscopy, X-ray diffraction and Rutherford backscattering techniques.
Abstract: Room temperature interdiffusion studies of Au/Sn thin film couples were made using transmission electron microscopy, X-ray diffraction and Rutherford backscattering techniques. Au/Sn thin film couples were found to interdiffuse at room temperature via both bulk and grain boundary diffusion mechanisms. In the bulk diffusion, gold diffuses interstitially into tin and initially forms AuSn 4 and AuSn intermetallic compounds. Grain boundary diffusion of tin into gold is also observed. The use of various thickness combinations in the thin film couples permitted detection of four intermetallics (ζ phase, AuSn, AuSn 2 and AuSn 4 ) which can form as a result of the interdiffusion. In addition, it was found that interdiffusion accompanied by the formation of hillocks and Kirkendall voids.
TL;DR: In this article, the variations in the structure and optical properties of TiO2 films produced by reactive d.c. plasmatron sputtering with the most important deposition parameters are investigated.
Abstract: We investigated the variations in the structure and optical properties of TiO2 films produced by reactive d.c. plasmatron sputtering with the most important deposition parameters. Over a wide range, the phase composition (ratio of rutile to anatase) and the grain size of the TiO2 films can be influenced in a controlled manner by variations in the substrate temperature and the oxygen partial pressure. Because of their high refractive index and low light-scattering losses, plasmatron-sputtered TiO2 films are of great interest in the field of optical interference coatings, e.g. for dielectric multilayer stacks.
TL;DR: In this paper, a pyrolytic hydrogen reduction of MoO2Cl2 in the temperature range 550-710°C on both quartz and metal substrates is described.
Abstract: Black molybdenum films combining a high IR reflectance with a significant solar absorptance were produced by the pyrolytic hydrogen reduction of MoO2Cl2 in the temperature range 550–710°C on both quartz and metal substrates. Characterization by X-ray, transmission electron microscopy, scanning electron microscopy and Auger analyses showed that the films are composite materials consisting of small molybdenum particles suspended in a matrix of MoO2 grains. The composition and structure of the films can be adjusted by variations in the substrate temperature and hydrogen concentration, resulting in corresponding changes in the optical properties. Although the films described here are comparable in structure with black chrome, they are more durable at elevated temperatures and were tested at 500°C in a roughing pump vacuum.
TL;DR: In this paper, a set of simple procedures for studying the growth modes of vacuum-deposited ultrathin films were proposed. But the assumptions made in these procedures are not carefully considered: (i) possible changes in the sticking probability at certain coverages; (ii) dissolution of the deposited material; (iii) anomalous variations in the parameters describing the emission and attenuation of the Auger electrons (possibly due to diffraction); (iv) the possibility of growth modes in which multiple layers form simultaneously (the n th layer starting before the ( n − 1
Abstract: Auger electron spectroscopy provides apparently simple procedures for studying the growth modes of vacuum-deposited ultrathin films. Mistakes of interpretation can occur, however, if certain factors are not carefully considered: (i) possible changes in the sticking probability at certain coverages; (ii) dissolution of the deposited material; (iii) anomalous variations in the parameters describing the emission and attenuation of the Auger electrons (possibly due to diffraction); (iv) the possibility of growth modes in which multiple layers form simultaneously (the n th layer starting before the ( n −1)th layer is complete); (v) kinetic effects due to agglomeration; (vi) the effect of adsorbed impurities on the growth mode. These points are examined and a scheme for a set of procedures is proposed.
TL;DR: The density or porosity of these coatings is largely dictated by the structure of the colloidal species in the dispersion as discussed by the authors, which can be provided for protective applications such as corrosion resistance, whereas porous coatings of high specific surface area find applications in catalysis.
Abstract: Ceramic oxide coatings may be applied to metal surfaces by the use of colloidal dispersions or aquo-sols of the corresponding hydrous oxides or hydroxides. The density or porosity of these coatings is largely dictated by the structure of the colloidal species in the dispersion. Dense coatings can be provided for protective applications such as corrosion resistance, whereas porous coatings of high specific surface area find applications in catalysis.
TL;DR: In this article, the possibility of determining transport parameters for the electrical conductivity from its dependence on the film thickness (size effect) is discussed, and the experimental curves have to be fitted for very small film thickness to permit a separation of these parameters.
Abstract: The possibility of determining transport parameters for the electrical conductivity from its dependence on the film thickness (size effect) is discussed. Measured conductivities are used to assess existing theories on the size effect. Only Namba's model can be fitted to experimental curves and this enables us to determine four parameters, namely the conductivity σ∞, the mean free path l∞, the specularity parameter p and the surface roughness h. The experimental curves have to be fitted for very small film thickness to permit a separation of these parameters. The most important thickness range is just that which in the past has usually been excluded from discussion. Careful experiments and careful computer fittings will enable investigations of electronic states in distorted metal films.
TL;DR: In this paper, a theoretical analysis of the deformation of foils in the biaxial bulge test was made and the relationship between stress and strain on the one hand and the pressure and height of the bulge on the other hand was established as a function of the Poisson's ratio and the crystal symmetry.
Abstract: A theoretical analysis was made of the deformation of foils in the biaxial “bulge test”. The relationship between stress and strain on the one hand and the pressure and height of the bulge on the other hand was established as a function of the Poisson's ratio and the crystal symmetry. For strains less than 1% Beams' formulae were found to be accurate to within 8%. The distribution of stresses and strains and the curvature throughout the bulge was also determined. Expressions for the biaxial elastic modulus Y[hkl], measured from the slope of the stress-strain curve of a bulge test, were derived for (100), (110) and (111) crystallographic orientations of the film plane in cubic crystals. A bulge tester was constructed and stress-strain curves were obtained for copper and CuNi homogeneous foils. The measured biaxial moduli Y[111] for both copper and 50at.%CuNi foils having strong 〈111〉 texture were in excellent agreement with those calculated from the bulk alloy elastic constants. Satisfactory agreement was also found between measured and calculated values of Y[100] for films with a 〈100〉 texture.
TL;DR: In this article, the friction and wear behavior of a number of refractory coatings, such as TiC, TiN, SiC, Cr7C3, FexB and Al2O3, under different environmental conditions are discussed.
Abstract: When steel and nickel-based alloys are to be used as substrate materials for the chemical vapour deposition of hard wear-resistant and corrosion-protective coatings because of their high mechanical strength, the criteria for choosing the correct grade have to be established. In this paper we contribute towards this goal. We also discuss the friction and wear behaviour of a number of refractory coatings, such as TiC, TiN, SiC, Cr7C3, FexB and Al2O3, under different environmental conditions. Some industrial tribological applications at moderately high temperatures (350°C in a helium atmosphere) or where the environment precludes the use of fluid lubricants are presented to illustrate the technical and economic feasibility and the usefulness of such coated machine elements and wear parts. Finally we deal with a very special application, the industrial exploitation of which is only just beginning: a multiple refractory compound coating to improve the protection of niobium tubes in the core of a nuclear reactor from damage due to metallurgical corrosion by liquid steel at high temperature (1600°C) which would result from accidental failure of a fuel pin.
TL;DR: In this article, the incremental compressive stress in polycrystalline TiC films with thickness between 0.1 and 2.8 microm were found to be in a state of compression.
Abstract: Polycrystalline TiC films with thickness between 0.1 and 2.8 microm were deposited by r.f. sputtering onto 1010 steel and borosilicate glass substrates at 200°C. All films were found to be in a state of compression. For a film grown under a given set of deposition conditions, the incremental compressive stress, i.e. the average stress in the uppermost deposited layer, was generally found to be largest near the film-substrate interface and to become constant with film thickness tf for tf ≳ 0.3 microm. However, for a given tf the incremental stress increased with a decrease in the argon sputtering pressure PAr. Experimental results showed that the incremental compressive stress in bulk films could be directly related to the trapped argon concentration. Argon incorporation is due to the burial of energetic species incident on the growing film surface from two primary sources: energetic neutrals produced by Ar+ ions scattered off the target in binary collisions and Ar+ ions accelerated to the substrate owing to its induced negative potential with respect to the positive space charge region in the r.f. discharge. The trapped argon concentration from both contributions increased with decreasing PAr. All films grown on steel substrates exhibited good adhesion as indicated by indentation and diamond stylus scratch tests. The residual compressive stress in the films was found to be beneficial for wear-related applications in which the film was subjected to a large tensile stress.
TL;DR: In this article, a model of the scratch test is developed which incorporates the effects of friction in the analysis and provides an explanation for the scanning electron microscopy observations, which has a history of successful use in investigations of adhesion and of aging effects in adhesion.
Abstract: The scratch test has a history of successful use in investigations of adhesion and of aging effects in adhesion. Observations in the scanning electron microscope have shown the process of coating removal to be complex and have cast doubt on the method. A model of the scratch test is developed which incorporates the effects of friction in the analysis and provides an explanation for the scanning electron microscopy observations.
TL;DR: In this article, the effects of the additional selenium on the properties of the films were investigated by structural investigations and photoconductivity measurements, and it was found from the results of the present measurements that compositional changes occur in the films with increasing Selenium/InSe ratio and that single-phase films containing only InSe are obtained at a certain critical ratio.
Abstract: Films were formed by alternately evaporating InSe and Selenium from separate evaporation sources onto glass substrates kept at temperatures below 150°C with subsequent thermal annealing. The effects of the additional selenium on the properties of the films were investigated by structural investigations and photoconductivity measurements. It is found from the results of the present measurements that compositional changes occur in the films with increasing selenium/InSe ratio and that single-phase films containing only InSe are obtained at a certain critical ratio. The refractive indices and absorption coefficients of amorphous and crystalline InSe films in the spectral range 0.6–2.5 μm are determined by spectrophotometric reflectance and transmittance measurements. The minimum optical energy gap obtained from measurements of the absorption spectrum for the crystalline films is close to the value for single crystals. A heterostructure diode using crystalline InSe films as “window layers” was prepared and the fundamental photovoltaic properties were investigated. An absolute quantum efficiency of about 18% is obtained in the wavelength range 1.1–1.25 μm.
TL;DR: In this article, chemical vapor deposition (CVD) was used for the preparation of ZrB2 and TiB2 for photothermal solar absorber applications using CVD techniques.
Abstract: Coatings of ZrB2 and TiB2 for photothermal solar absorber applications were prepared using chemical vapor deposition (CVD) techniques. Oxidation tests suggest a maximum temperature limit for air exposure of 600 K for TiB2 and 800 K for ZrB2. Both materials exhibit innate spectral selectivity with an emittance at 375 K ranging from 0.06 to 0.09, a solar absorptance for ZrB2 ranging from 0.67 to 0.77 and a solar absorptance for TiB2 ranging from 0.46 to 0.59 ZrB2 has better solar selectivity and more desirable oxidation behavior than TiB2. A 0.071 μm antireflection coating of Si3N4 deposited onto the ZrB2 coating leads to an increase in absorptance from 0.77 to 0.93, while the emittance remains unchanged.
TL;DR: Hard i-C films are produced by ionizing a hydrocarbon compound, which is possibly dissociated and accelerated in an electric field towards the substrate where the film is grown as mentioned in this paper.
Abstract: Hard i-C films are produced by ionizing a hydrocarbon compound, which is possibly dissociated and accelerated in an electric field towards the substrate where the film is grown. The deposition takes place at a moderately low pressure. Carbon films grown in this way have some remarkable properties: they are insulating (10 7 –10 14 Ω cm) and have a negative temperature coefficient of conductivity, a high dielectric stregth, extreme hardness (a microhardness of 3000 HV or more), chemical inertness towards acids and organic solvents, an optical bandgap of 1–2 eV and the possibility of being doped. Depending on the fabrication process the properties of the film will vary from ones similar to those of bulk diamond to ones similar to those of amorphous carbon. For substrates on which carbides can be formed, the film and substrate will form a continuously integrated system over the interface layers.
TL;DR: In this article, the authors extend the previous study to include TiN coated onto three types of steel by reactive ion plating and show that the loadbearing capacity varies with the coating thickness for a given steel substrate.
Abstract: A previous study has shown that the scratch test for the measurement of adhesion can be used to assess the load-bearing capacity of a hard coating/steel substrate composite material. In the present work we extend the previous study to include TiN coated onto three types of steel by reactive ion plating. The mode of coating removal is studied and the critical load for the onset of removal is measured. The results are interpreted as showing that the load-bearing capacity varies with the coating thickness for a given steel substrate. Comparison with previous work indicates that the load-bearing capacity (adhesion) of the present samples corresponds well to that of the previously studied chemically vapour-deposited coatings.