Showing papers on "Thin film published in 1988"
TL;DR: Vapor-grown diamond and diamondlike materials may have eventual applications in abrasives, tool coatings, bearing surfaces, electronics, optics, tribological surfaces, and corrosion protection.
Abstract: Diamond may be grown at low pressures where it is the metastable form of carbon. Recent advances in a wide variety of plasma and electrical discharge methods have led to dramatic increases in growth rates. All of these methods have certain aspects in common, namely, the presence of atomic hydrogen and the production of energetic carbon-containing fragments under conditions that support high mobilities on the diamond surface. Some understanding of the processes taking place during nucleation and growth of diamond has been achieved, but detailed molecular mechanisms are not yet known. Related research has led to the discovery of a new class of materials, the "diamondlike" phases. Vapor-grown diamond and diamondlike materials may have eventual applications in abrasives, tool coatings, bearing surfaces, electronics, optics, tribological surfaces, and corrosion protection.
1,391 citations
Patent•
02 Mar 1988TL;DR: In this paper, an electroluminescent device with a luminescent zone of less than one μm in thickness comprised of an organic host material capable of sustaining hole-electron recombination and a fluorescent material able of emitting light in response to energy released by hole-conducting electron recombination is described.
Abstract: An electroluminescent device is disclosed having a luminescent zone of less than one μm in thickness comprised of an organic host material capable of sustaining hole-electron recombination and a fluorescent material capable of emitting light in response to energy released by hole-electron recombination.
1,228 citations
TL;DR: In this paper, quaternary stannite-type semiconductor films of Cu2CdSnS4 and Cu2ZnSnSS4 with (112) orientation were deposited on heated glass substrates using atom beam sputtering.
Abstract: Quaternary stannite-type semiconductor films of Cu2CdSnS4 and Cu2ZnSnS4 with (112) orientation were deposited on heated glass substrates using atom beam sputtering. These p-type films showed resistivities which were decreasing functions of the substrate temperature up to 240°C. The films had an absorption coefficient larger than 1 × 104 cm-1 in the visible wavelength range. The direct optical band gaps of the (112) oriented polycrystalline films were estimated as 1.06 eV and 1.45 eV for Cu2CdSnS4 and Cu2ZnSnS4, respectively.
900 citations
TL;DR: Optical band gaps, evaluated from spectrophotometric data, were widened in proportion to the Al doping, and could be quantitatively reconciled with an effective-mass model for n-doped semiconductors, provided the polar character of ZnO was accounted for.
Abstract: Films of ZnO:Al were produced by weakly reactive dual-target magnetron sputtering. Optical band gaps, evaluated from spectrophotometric data, were widened in proportion to the Al doping. The widening could be quantitatively reconciled with an effective-mass model for n-doped semiconductors, provided the polar character of ZnO was accounted for.
829 citations
TL;DR: In this article, the sputter deposition of superconducting Bi-Sr-Ca-Cu-O thin films was studied with particular reference to the relation between the deposition conditions and the superconding properties of the obtained.
Abstract: The sputter deposition of superconducting Bi-Sr-Ca-Cu-O thin films was studied with particular reference to the relation between the deposition conditions and the superconducting properties of the films obtained. After annealing, the films sputtered from a sintered Bi1.3Sr1Ca1Cu1.5Ox target exhibited superconductivity with zero-resistance at 83 K. The possibility of obtaining high-Tc superconducting film without post-deposition annealing was also demonstrated.
731 citations
TL;DR: In this article, the atomic bonding configurations of carbon bonding in diamond and diamond-like thin films are explored using Raman scattering, and the general aspects of Raman scatter from composites are presented.
Abstract: The atomic bonding configurations of carbon bonding in diamond and diamondlike thin films are explored using Raman scattering. The general aspects of Raman scattering from composites are presented. Effects are discussed due to crystalline or amorphous structures, large versus microcrystalline domains, and strong optical absorption and transparent regions. The Raman scattering from diamondlike films shows several features which are attributed to microcrystalline graphitelike structures which all originate from the same region in the sample. In contrast, the spectra of diamond films show features attributed to different components of a composite film. Components identified are crystalline diamond, and disordered and microcrystalline graphitic structures. The presence of precursor microcrystalline or amorphous diamond structures is also suggested.
641 citations
TL;DR: In this article, a crack-free transparent ferroelectric polycrystalline Pb(Zr,Ti)O3 thin films were prepared by spin-coating solutions of complex alkoxides.
Abstract: Crack‐free transparent ferroelectric polycrystalline Pb(Zr,Ti)O3 thin films were prepared by spin‐coating solutions of complex alkoxides. The preparation of stock solution, firing, and annealing of films was described. The coating of the intermediate layer of Al2O3 increased the adhesion between Pb(Zr,Ti)O3 thin films and glass substrates. The crystalline phases of films with varying Zr/Ti ratios were investigated. The dielectric constants were about 260. The remanent polarization and coercive field were 6.6 μC/cm2 and 26.7 kV/cm, respectively. The refractive index of the perovskite Pb(Zr,Ti)O3 films was 2.6 at 6328 A, and the absorption edge was at 3400 A. The quadratic and linear electro‐optic effects were measured with respect to the Zr/Ti ratio from 40/60 to 60/40 for films grown on glass substrates. The quadratic and linear electro‐optic coefficients were about 1×10−18 m2 /V2 and 2.4×10−11 m/V at 6328 A, respectively.
608 citations
TL;DR: In this paper, the theory of nucleation and growth of thin films is reviewed and the basic phenomena on the substrate have been described, followed by the representation of the mathematical theories of the growth of the thin films in the initial stage and the description of experimental studies.
581 citations
TL;DR: In this paper, a self-assembled, supported organic monolayer films are used to study problems in the physical-organic chemistry and materials science of organic surfaces, especially the relation between the molecular-level structure of the film constituents and the macroscopic properties of the assembled monolayers.
Abstract: : Exposure of evaporated gold films supported on silicon wafers to solutions of dialkyl sulfides (R(CH2)m-S-(CH2)n-R'; R and R'=CH3 or CO2H) or alkyl thiols (R(CH2)nSH, R=CO2H or CH3) in methanol or ethanol results in rapid formation of a monolayer of the organosulfer compound adsorbed onto the gold. The resulting films have been characterized using a number of techniques, including X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IRS), ellipsometry, and wetting. These self-assembled, supported organic monolayer films are systems that can be used to study problems in the physical-organic chemistry and materials science of organic surfaces, especially the relation between the molecular-level structure of the film constituents and the macroscopic properties of the assembled monolayers. Keywords: Thin film, Monolayer, Surface spectroscopy, electronic materials
579 citations
TL;DR: In this paper, the stresses that develop in thin films on substrates can be detrimental to the reliability of thin film electronic devices, in order to design these devices for improved mechanical reliability, an...
Abstract: The stresses that develop in thin films on substrates can be detrimental to the reliability of thin film electronic devices. In order to design these devices for improved mechanical reliability, an...
560 citations
TL;DR: Results show that two molecularly smooth surfaces, when close together in simple liquids, slide (shear) past each other while separated by a discrete number of molecular layers, and that the frictional force is "quantized" with the number of layers.
Abstract: An experimental technique is described for simultaneously measuring the static and dynamic interactions of very thin liquid films between two surfaces as they are moved normally or laterally relative to each other. Film thickness can be measured and controlled to 1 angstrom. Initial results are presented of the transition in the physical properties of liquid films only one molecular layer thick to thicker films whose properties are practically indistinguishable from the bulk. In particular, the results show that two molecularly smooth surfaces, when close together in simple liquids, slide (shear) past each other while separated by a discrete number of molecular layers, and that the frictional force is "quantized" with the number of layers.
TL;DR: Reference LPI-ARTICLE-1988-002doi:101021/ja00212a033View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12 as discussed by the authors.
Abstract: Reference LPI-ARTICLE-1988-002doi:101021/ja00212a033View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12
TL;DR: Dip coating is a simple old way of depositing onto a substrate, especially small slabs and cylinders, a uniform thin film of liquid for solidification into a coating.
Abstract: Dip coating is a simple old way of depositing onto a substrate, especially small slabs and cylinders, a uniform thin film of liquid for solidification into a coating. The basic flow is steady, and in it film thickness is set by the competition among viscous force, capillary (surface tension) force and gravity. Thickness and uniformity can be sensitive to flow conditions in the liquid bath and gas overhead. The faster the substrate is withdrawn, the thicker the film deposited. This can be countered by using volatile solutes and combining rapid enough drying with the basic liquid flow. Then the physics grows more complicated, theoretical prediction of process performance more difficult, and control of the process more demanding. Outside product RD actually it is often modified.
TL;DR: In this article, an effective mass model for n-doped semiconductors is proposed for n−doped polysilicon, where the Al atoms act as pointlike Coulomb scatterers and are screened by the electrons acco...
Abstract: ZnO:Al coatings were prepared by rf magnetron sputtering of ZnO together with dc magnetron sputtering of Al onto rapidly revolving unheated substrates under weakly oxidizing conditions. Optimized films had ∼1% luminous absorptance, ∼85% thermal infrared reflectance, and ∼5×10−4 Ω cm electrical resistivity at a thickness of ∼0.3 μm. The Al content was ≲2 at. %, as determined by Rutherford backscattering spectrometry. Transmission electron microscopy and electron diffraction showed ∼50‐nm average crystallite size and a hexagonal wurtzite structure. Spectrophotometric transmittance and reflectance were recorded in the 0.2–50‐μm wavelength interval, and the complex dielectric function was evaluated by computation. The optical data were explained from an effective mass model for n‐doped semiconductors. The Al atoms are singly ionized, and the associated electrons occupy the bottom of the conduction band as free‐electron gas. The Al ions act as pointlike Coulomb scatterers and are screened by the electrons acco...
TL;DR: In this article, the magnetic anisotropy of Co ultrathin films sandwiched by Au was investigated and it was shown that the easy magnetization direction becomes perpendicular to the film plane for Co thicknesses lower than 11 A.
Abstract: We present experimental and theoretical investigations on the magnetic anisotropy of Co ultrathin films sandwiched by Au. Ferromagnetic resonance experiments revealed the presence of a large perpendicular surface anisotropy that makes the easy magnetization direction become perpendicular to the film plane for Co thicknesses lower than 11 A, as is observed in magnetization measurements. In order to explain this surface anisotropy, we propose various models, taking into account the imperfections of the films. For thicknesses below 11 A, there is a large increase of the coercive field with decreasing thickness. This effect is tentatively interpreted in a model of propagating Bloch walls, where the interfacial roughness plays an important role.
TL;DR: In this paper, the Young's moduli and the yield strengths of thin-film materials that comprise the beams are determined using simple beam theory and the load-deflection data, the measured mechanical properties are compared to those obtained by indenting similar thin films supported by their substrate.
Abstract: The mechanical deflection of cantilever microbeams is presented as a new technique for testing the mechanical properties of thin films. Single-layer microbeams of Au and SiO2 have been fabricated using conventional silicon micromachining techniques. Typical thickness, width, and length dimensions of the beams are 1.0,20, and 30 μm, respectively. The beams are mechanically deflected by a Nanoindenter, a submicron indentation instrument that continuously monitors load and deflection. Using simple beam theory and the load-deflection data, the Young’s moduli and the yield strengths of thin-film materials that comprise the beams are determined. The measured mechanical properties are compared to those obtained by indenting similar thin films supported by their substrate.
TL;DR: In this article, thin films of YBa2 Cu3 O7−x have been grown epitaxially in c-axis orientation on 〈100〉 SrTiO3 by pulsed excimer laser evaporation from a stoichiometric 1 −2 −3 target.
Abstract: Thin films of YBa2 Cu3 O7−x have been grown epitaxially in c‐axis orientation on 〈100〉 SrTiO3 by pulsed excimer laser evaporation from a stoichiometric 1‐2‐3 target. The substrate temperature was adjusted between 720 and 780 °C, and the oxygen partial pressure during the deposition was chosen in the range 0.1–0.3 mbar. Cooled to ambient temperature in situ for 1 h in flowing oxygen gas, the films showed complete diamagnetism and zero resistance at 90 K with a transition width of 2 K. Critical current densities of 2.2×106 A/cm2 in zero magnetic field and 1.5×105 A/cm2 at 2 T were measured at 77 K. The resistivity at 100 K was about 60 μΩ cm.
TL;DR: Co-Au multilayers with Co layer thicknesses between 22 and 5 \AA{}A, prepared by ion-beam sputtering, have an easy-plane magnetic anisotropy, which is attributed to a stronlgy enhanced interface anisotropic enhancement, due to sharpening of the interfaces as revealed by x-ray diffraction.
Abstract: Co-Au multilayers with Co layer thicknesses between 22 and 5 \AA{}A, prepared by ion-beam sputtering, have an easy-plane magnetic anisotropy Their saturation magnetization indicates the presence of diffuse interfaces, caused by ion-beam mixing Annealing of the multilayers at 250-300\ifmmode^\circ\else\textdegree\fi{}C leads to a perpendicular anisotropy for Co thicknesses below about 14 \AA{}A This effect is attributed to a stronlgy enhanced interface anisotropy, which is due to sharpening of the interfaces as revealed by x-ray diffraction
TL;DR: In this paper, the results of three methods used to attain high power densities in solid polymer electrolyte fuel cell systems were presented, i.e., use of a higher wt% Pt/C in the supported electrocatalysts, sputtering of a thin film of platinum (corresponding to a 50 nm film on a smooth surface) on the Prototech electrode, and a combination of the two methods.
TL;DR: In this paper, the angular distribution of the composition and thickness of the Y•Ba•Cu oxide film deposited by firing excimer laser (30 ns, 248 nm) pulses at a stoichiometric Y1Ba2Cu3O7−x pellet was measured using Rutherford backscattering technique.
Abstract: Using Rutherford backscattering technique, we have measured the angular distribution of the composition and thickness of the Y‐Ba‐Cu oxide film deposited by firing excimer laser (30 ns, 248 nm) pulses at a stoichiometric Y1Ba2Cu3O7−x pellet. The angular distribution consisted of two distinct components: one a cos θ component, a result of evaporation, and the other a highly forward directed component, a result of a secondary ejection process. The evaporated component is nonstoichiometric, as one would expect, whereas the forward‐directed component has a composition close to that of the pellet. Further, the forward‐directed stoichiometric component increases with the laser energy density in comparison with the evaporated component. These observations are discussed in the context of current models of laser‐induced material ejection at surfaces.The laser energy dependence of the deposition is of critical importance in controlling the film stoichiometry.
TL;DR: La viscosite dynamique apparente a 1Hz de liquides non-polaires, confirmes entre les plateaux paralleles d'un mica atomiquement doux, est considerablement augmentee par rapport a celle des fluides isotropres and presente une grande dependance vis-a-vis de the pression.
Abstract: We study the resistance to sliding of liquid films 1-6 molecules thick. The apparent dynamic viscosity at 1 Hz of nonpolar liquids confined between parallel plates of atomically smooth mica is considerably enhanced over that of the isotropic fluids and shows extreme dependence on pressure. Rapid, reversible switching between liquidlike and noncompliant responses as a function of small changes in normal pressure is also found, suggesting a phase transition to a solidlike structure.
TL;DR: In this article, a superconducting thin film of yttria-stabilized zirconia substrates using metal trifluoroacetate spin-on precursors is presented.
Abstract: Superconducting thin films of Y‐Ba‐Cu oxide have been prepared on yttria‐stabilized zirconia substrates using metal trifluoroacetate spin‐on precursors. The films exhibit an extremely sharp resistive transition with zero resistance at temperatures as high as 94 K. The superconducting phase is formed by a three‐step process: (a) decomposition of the spun‐on trifluoroacetate film to the fluorides, (b) conversion of the fluorides to oxides by reacting with water vapor, and (c) annealing followed by slow cooling in oxygen. The properties of the films depend on the amount of conversion of the fluorides by reaction with water. Films which show the presence of some unreacted barium fluoride have strong c‐axis normal preferred orientation, with a sharp resistive transition. When all the barium fluoride is converted, the film is more randomly oriented and exhibits a broader transition to zero resistance.
TL;DR: In this paper, the average grain size of the crystallized amorphous silicon films depends on the annealing temperature and the deposition conditions, and the final grain size is also influenced by the annaling temperature with the largest grain size obtained at low-annealing temperatures.
Abstract: The crystallization of undoped amorphous silicon films deposited by low‐pressure chemical vapor deposition in the temperature range 580–530 °C and annealed from 550 to 950 °C has been studied by transmission electron microscopy. The average grain size of the crystallized films depends on the annealing temperature and the deposition conditions. The nucleation rate of new grains during annealing decreases as the deposition temperature decreases from 580 to 545 °C and/or when the deposition rate increases. The final grain size is also influenced by the annealing temperature with the largest grain size obtained at low annealing temperatures. A simple model is described which explains the dependence of grain size on the annealing temperature. An average grain size of 500 nm has been obtained in a 200‐nm film deposited at 545 °C and annealed at 550 °C.
TL;DR: In this paper, the authors classify thin-film deposition by laser evaporation into equilibrium and none-quilibrium processes according to the ways in which the source materials are vaporized.
Abstract: Among the various material growth techniques, physical vapor deposition of thin films encompasses many experimental forms. They can be categorized into equilibrium and none-quilibrium processes according to the ways in which the source materials are vaporized. Equilibrium process is typified by thermal evaporation including the conventional resistive heating, the more elaborate e-beam evaporation. as well as molecular beam epitaxy (MBE). Nonequilibrium processes include sputtering and many of its derivative forms such as ion beam deposition. In comparison with these techniques, thin-film deposition by laser evaporation is less well known and does not fall cleanly into either category. Depending on the laserconditions, the evaporation process can be either thermal, nonthermal, or a mixture of the two.
TL;DR: Amorphous carbon nitride thin films have been grown by plasma decomposition of a feedstock of CH4 and N2 as mentioned in this paper, and the optical absorption and photoluminescence spectra show that nitrogen incorporation decreases the bandgap and increases the structural order of these thin films.
TL;DR: In this paper, a single-crystal thin film with the c axis perpendicular to the substrate plane has been grown on the (100) surface of SrTiO3 and the substrate temperature was kept below 600°C and the oxidation treatment was performed at below 500°C.
Abstract: By means of the activated reactive evaporation, YBa2Cu3O7-x single-crystal thin films with the c axis perpendicular to the substrate plane have been directly and epitaxially grown on the (100) surface of SrTiO3. The substrate temperature was kept below 600°C and the oxidation treatment was performed at below 500°C. The ac-resistive measurement for a film with 2000 A thickness gave a sharp superconducting transition, where the endpoint was 90.2 K and ΔTc(10–90%)=1.7 K. From the complex susceptibility measurement we confirmed the Meissner effect as well as the structural uniformity of the specimen.
TL;DR: In this paper, the process of spin coating is described, with particular attention to applications in microelectronics, and the physical mechanisms involved in the process are discussed and those mechanisms that affect the final state are identified, viz., centrifugal and viscous forces, solute diffusion, and solvent evaporation.
Abstract: The process of spin coating is described, with particular attention to applications in microelectronics. The physical mechanisms involved in the process are discussed and those mechanisms that affect the final state are identified, viz., centrifugal and viscous forces, solute diffusion, and solvent evaporation: A model is proposed that incorporates only the latter mechanisms, with viscosity and diffusivity depending on solute concentration. The evaporation of solvent during spinning causes the solution viscosity to increase and the flow is reduced. The thickness of the final solid film is related to the thickness of a diffusion boundary layer near the free surface. The model predicts the final dry film thickness in terms of the primary process variables, spin speed, and initial polymer concentration. A similarity boundary‐layer analysis leads to a simple approximate result for the final film thickness that is consistent with limited experimental data, hf ∼KC0(ν0D0)1/4/Ω1/2, where K is a number of order un...
TL;DR: In this article, thin layers of ZnO were grown on (0001) oriented sapphire by organometallic chemical vapor deposition, and low-temperature photoluminescence indicates that near-band edge luminescence dominates the spectrum.
Abstract: Thin layers of ZnO were grown on (0001) oriented sapphire by organometallic chemical vapor deposition. Low‐temperature photoluminescence indicates that near‐band‐edge luminescence dominates the spectrum. In contrast to bulk grown material deep level luminescence for the layers is relatively weak.
Book•
01 Jan 1988
TL;DR: Theoretical background experimental methods for measuring the optical constants of bulk materials Kramers-Kronig methods for calculating optical constants results for bulk specimens thin films determination of the optical constant of thin films results for thin films the optics of discontinuous films applications of optical thin films.
Abstract: Theoretical background experimental methods for measuring the optical constants of bulk materials Kramers-Kronig methods for calculating optical constants results for bulk specimens thin films determination of the optical constants of thin films results for thin films the optics of discontinuous films applications of optical thin films.
TL;DR: In this paper, surface micromachining is used to fabricate beams, plates, sealed cavities, and linear and rotary bearings, with an emphasis on polysilicon microstructures.
Abstract: Micromechanical structures can be made by selectively etching sacrificial layers from a multilayer sandwich of patterned thin films. This paper reviews this technology, termed surface micromachining, with an emphasis on polysilicon microstructures. Micromechanical characteristics of thin‐film microstructures critically depend on the average residual stress in the film, as well as on the stress variation in the direction of deposition. The stress in low‐pressure chemical vapor deposition polysilicon varies with deposition temperature, doping, and annealing cycles. Applications of surface micromachining to fabricate beams, plates, sealed cavities, and linear and rotary bearings are discussed.