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Journal of Applied Physics

Issue 2 • Date Jan 1989

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Displaying Results 1 - 25 of 78
  • Analysis and assessment of electromagnetic ring expansion as a high‐strain‐rate test

    Page(s): 411 - 422
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    The rapid expansion of electromagnetically launched thin metal rings is analyzed in detail, with particular emphasis on the determination of the expansion speed, currents, and specimen temperature as a function of launch voltage. Electrodynamic calculations for copper, tin, and lead rings are presented and compared with typical experimental results. Currents derived from Rogowski‐probe records and expansion speeds measured with a velocity interferometer (VISAR) are found to be in excellent agreement with these calculations. Currents are large, of the order of tens of kiloamperes, and heating of the specimen can be significant. It is found that, for good conductors such as copper, the maximum useful strain rate will be limited by the Joule heating of the specimen. For materials with resistivities and strengths substantially larger than those of copper, direct expansion of a specimen ring is difficult. Use of a composite ring, in which a high‐conductivity driver is used to launch a low‐conductivity specimen, is discussed as a means of overcoming this limitation. View full abstract»

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  • Thermal fixing of holographic gratings in Bi12SiO20

    Page(s): 423 - 427
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    Fixing of holographic gratings in Bi12SiO20 single crystals has been obtained using a thermal process. The properties of the fixed gratings suggest that the charges responsible have an ionic nature. The study of thermal erasure of the fixed gratings provides a value of 1.44 eV for the activation energy and 0.03 cm2 s-1 for the preexponential factor for diffusion of these charges. View full abstract»

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  • Property of amplified spontaneous emission and saturable absorber for a terawatt XeCl laser system

    Page(s): 428 - 432
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    A peak power of 1 TW has been obtained in XeCl with a pulse width of 310 fs and the amplified spontaneous emission (ASE) less than 3% in energy. The property of ASE was analyzed for different gains. Based on this analysis, the ASE coupling between stages was suppressed by using an appropriate spatial filter along with operating at a low‐gain level. The saturation characteristics of UV dyes were investigated and analyzed for subpicosecond pulses. BBQ [4,4’’’di(2‐butyl‐octoxy‐1)‐p‐quarter‐phenyl)] in cyclohexane showed the satisfactory performance for a saturable absorber in contrast and transmission. View full abstract»

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  • A model for evaluating the efficiency of an interdigital transducer for bulk wave excitation into liquid

    Page(s): 433 - 437
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    An equivalent circuit model analysis of a liquid‐loaded interdigital transducer is described. The electric loss related to the complex relative dielectric constant and the electroacoustic conversion efficiency are represented in the form of a function of the specific acoustic impedance (ρv) of the loaded liquid. The conversion efficiency for ultrasound into the liquid is estimated from only the acoustic impedance and the relaxation time of the substrate material, which are obtained relatively easily from the water measurement. The estimated theoretical efficiency is in good agreement with the experimental results for various liquids. These results also coincide with the results from the wave equation for the leaky surface acoustic wave propagation at the solid–liquid boundary. View full abstract»

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  • Separation of surface and volume absorption by photothermal deflection

    Page(s): 438 - 447
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    A complete theoretical treatment of sine‐wave photothermal deflection spectroscopy in a sample that includes surface absorption and bulk absorption is given. The results can be used to separate surface absorption from bulk absorption, and the surface absorption by almost all optical coatings can be measured by this method. The theoretical results have been verified experimentally. View full abstract»

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  • Extreme‐ultraviolet illumination effects on the PBFA‐I magnetically insulated ion diode

    Page(s): 448 - 463
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    We have examined the effect of illuminating the anode in the Applied‐B ion diode in Sandia’s PBFA‐I accelerator with 60–100 kW/cm2 of extreme‐ultraviolet (XUV) photons a few hundred nanoseconds prior to the accelerator shot. We find that XUV illumination significantly shortens the turn‐on time of the ion beam, especially under conditions in which the normal ‘‘flashover’’ ion‐source mechanisms are suppressed. In addition to the anticipated XUV photodesorption and photoionization of the anode material, some of the improvement seen with XUV illumination may be due to photoejection of electrons from the power feeds and their subsequent interaction with the anode source. Also, XUV illumination of a fine polypropylene weave located at the virtual cathode radius can preform the virtual cathode, dramatically reducing the turn‐on time of the ion beam in the diode. View full abstract»

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  • Anisotropy control in CF4 microwave plasma etching

    Page(s): 464 - 467
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    A parametric study of the etching of silicon with CF4 has been performed in a multipolar microwave plasma with independent rf biasing. According to the plasma conditions, up to three transitions from anisotropic to nonanisotropic etching can be found. The mechanisms involved are discussed in terms of the coadsorption of reactive fluorine atoms and CFx radicals which are responsible for the wall passivation by polymer formation. View full abstract»

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  • Measurement of ion temperatures by means of Rutherford scattering of energetic neutrals above the limiting angle

    Page(s): 468 - 473
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    A technique to measure the ion temperature in a thermonuclear plasma is proposed, based on Rutherford scattering of a beam of energetic neutral particles by the plasma ions. If the mass of the beam particles, mb, is larger than the mass of the scattering ions, mp, a sharp maximum (limiting) angle θlim=sin-1(mp/mb) exists in case the thermal velocities of the plasma ions are neglected. When the scattering ions have thermal velocities, however, scattering of beam particles can occur through angles larger than θlim. Measurement of the intensity of particles above the limiting angle can be used to find the temperature of the plasma ions, with a 10% accuracy and a spatial and temporal resolution of 10 cm and a few μs, respectively, provided the ion velocity distribution is Maxwellian. A feasibility study elucidates that this method can also be used to measure the temperature of a 3He minority component. View full abstract»

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  • Interfacial reactions on annealing molybdenum‐silicon multilayers

    Page(s): 474 - 480
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    The structure and interfacial reaction in sputtered Mo‐Si multilayers have been studied using cross‐section transmission electron microscopy, electron diffraction, Rutherford backscattering, and low‐angle x‐ray diffraction. Low‐temperature (T≪550 °C) annealing was performed in a rapid‐thermal‐annealing furnace and in situ in the microscope. No solid‐state amorphization was observed, in spite of the presence of amorphous alloy interfacial layers in the as‐deposited structure. Instead, the amorphous interlayers crystallize, and growth of the crystalline product, hexagonal‐MoSi2, proceeds. The bilayer period contracts during the reaction, as the disilicide is more dense than its constituents. View full abstract»

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  • Fe implantation in In0.53Ga0.47As/InP

    Page(s): 481 - 485
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    Single and multiple energy Fe+ implants are performed in n‐type InGaAs. Rapid thermal and furnace annealings are used to activate the implanted material. Surface Fe accumulation, multiple Fe peaks, and deep in‐diffusion of Fe are observed in the secondary ion mass spectrometry profiles of the implanted material. The crystal lattice perfection of the annealed material is evaluated qualitatively by photoreflectance measurements. A maximum resistivity of 4750 Ω cm is measured in the implanted material. View full abstract»

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  • Dual implant into GaAs with Si+ and Sn+ ions

    Page(s): 486 - 490
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    Undoped GaAs (100) wafers were implanted with 150‐keV Sn+ and/or 50‐keV Si+ ions to doses of 5×1013–1×1014/cm2 at room temperature, and annealed at 850 °C for 15 min. The backscattering spectra showed a sufficient crystalline recovery at this annealing condition. The transmission electron microscopy results indicated a significant difference between the samples of Sn+, Si+, and (Sn++Si+) implants in shape, size, and density of dislocations. The dislocations in the dual implant case were smaller than those of single implant in density and size. The electrical activation efficiencies of Sn+, Si+, and (Sn++Si+) implanted GaAs with a dose of 1×1014/cm3 for each ion specimen were 12%, 13%, and 6%, respectively. In the dual‐implant case, the carrier concentration was not simple addition of two doses and exhibited a saturation effect near 1×1018/cm3. View full abstract»

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  • The scattering of x rays from nonideal multilayer structures

    Page(s): 491 - 506
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    A general theory is developed for the scattering of x rays from a single nonideal interface between two dielectric media. It is then extended to describe the scattering of x rays from a multilayer structure composed of many nonideal interfaces. The most unique feature of this theory is that there are no constraints on the physical structure of the interfaces; the interfaces can have any form of roughness or compositional inhomogeneity. A simple analytical expression is derived for both the near and far radiation field to first order, assuming that the scattering is weak. The theory is valid for arbitrary polarization and at all angles of incidence (measured from the normal) less than the critical angle for total external reflection. Finally, the results are applied to study the effect of different interface structures on the performance of multilayer x‐ray optics. View full abstract»

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  • Radiation‐induced defect centers in glass ceramics

    Page(s): 507 - 514
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    Electron spin resonance (ESR) was used to characterize the radiation‐induced defect centers in low‐thermal‐expansion glass ceramics, including two types of Zerodur and Astrositall. The observed ESR spectra can be associated with different types of defect centers: a Zn+ center, several types of oxygen hole centers (OHCs), an aluminum‐oxygen hole center (Al‐OHC), an Fe3+ center, Ti3+ and Zr3+ centers, and three types of As centers. An Sb4+ center, which is not observed in Zerodur, is tentatively identified in Astrositall. From the effect of crystallization on the observed defect concentrations in Zerodur and computer simulation of the spectral lines of some of the centers, we infer that among the nine defect centers observed in the Zerodurs, the As‐associated centers are located in the glassy phase and/or at the interface between the glassy and crystalline phases, Zn+ and Al‐OHC are in the crystalline phase, and the rest (including most of the OHCs) are in the glassy phase. Radiation‐induced compaction in these materials appears to be related to the generation of OHCs in the glass phase. View full abstract»

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  • On the behavior of interaction of a Pt‐related center with radiation‐induced defects and the trace platinum detection

    Page(s): 515 - 518
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    The interaction of platinum (Pt) with electron irradiation‐induced defects has been observed. Platinum in silicon increases irradiation‐induced defects remarkably, especially the A center, and lowers the annealing temperature to 220 °C for the A center and to 140 °C for the divacancy and E center. The level Ea (0.23) in the Pt‐doped silicon is the Pt(-/0) level, an acceptor like the A center. A method is suggested for activating the platinum in silicon with low‐energy electron irradiation and subsequent thermal annealing and detecting it by deep level transient spectroscopy (DLTS). View full abstract»

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  • Defect production during ion implantation of various AIIIBV semiconductors

    Page(s): 519 - 526
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    The present paper gives a survey about the defect generation caused by ion implantation of GaAs, InAs, GaP, and InP. By combining Rutherford backscattering spectrometry, optical spectroscopy, and transmission electron microscopic methods, further information concerning the kinetics of the defect production as well as the type of defects created is obtained. Generally, the defect concentration in the region of implantation parameters investigated can be described by the energy density deposited into nuclear processes. Below critical values of the nuclear deposited energy density in GaAs weakly damaged layers containing point defects and point defect clusters are produced. With increasing nuclear deposited energy density an increasing number of amorphous zones is created due to manifold overlap of the initial defect clusters. The results indicate that in GaAs and InAs already at relatively low implantation temperatures, the amorphization occurs via homogeneous defect nucleation. The results obtained for GaP and InP, on the other hand, point at a remarkable contribution of heterogeneous defect nucleation already at room temperature, leading to amorphization at markedly lower nuclear deposited energy densities in spite of nearly identical values of the nuclear deposited energy. It is therefore concluded that defect recombination and annealing at room temperature is much less pronounced in the phosphides than in the arsenides. View full abstract»

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  • High‐speed liquid‐crystal modulators using transient nematic effect

    Page(s): 527 - 532
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    The transient nematic effect, together with multiple pass technique and optimal temperature effect, was employed to demonstrate high‐speed liquid‐crystal modulators. As a result, nematic liquid‐crystal modulators with frame time less than 50 μs have been achieved in the visible spectral region. View full abstract»

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  • The effects of target compliance on liquid drop impact

    Page(s): 533 - 540
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    When a liquid drop impacts a solid surface, the contact periphery at first expands more quickly than the compression wavefronts in either liquid or solid. The liquid behind the shock envelope is compressed and high pressures of order ρCV result, where ρ is the density of the liquid at ambient pressure, C the shock velocity in the liquid, and V the impact velocity. At a later stage, the shock envelope overtakes the contact periphery and a jetting motion, which releases the high pressures, commences. The magnitude and duration of the high pressures are critical in explaining the damage mechanisms and erosion processes caused by liquid impact. The experiments described in this paper use the two‐dimensional gel and photographic techniques developed for visualizing the shocks, recording the onset of jetting, and measuring jet velocities. This particular study is primarily concerned with the effect of target compliance on the early stages of impact. It is shown that the greater the target compliance, the longer the delay before jetting commences. Two critical conditions are shown to be useful in discussing jetting. The first defines when the shock envelope overtakes the contact periphery and liquid can ‘‘spall’’ into the air gap. The second defines when this spalled liquid appears ahead of the contact periphery as an observable jet. Both these conditions are investigated and the implications of the results for erosion damage are discussed. View full abstract»

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  • Deuterium magnetic resonance study of orientation and poling in poly(vinylidene fluoride) and poly(vinylidene fluoride‐co‐tetrafluoroethylene)

    Page(s): 541 - 547
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    Deuteron nuclear magnetic resonance line shapes are reported for oriented samples of poly(vinylidene fluoride) and an (80–20) copolymer of vinylidene fluoride and tetrafluoroethylene. For stretched samples the orientation of the chain axes with respect to the stretch direction is given by a Gaussian distribution of width ≊20°. The width of the distribution was slightly smaller in the more highly stretched copolymer. Surprisingly, as the magnetic field is rotated in the plane perpendicular to the stretch direction, the deuterium spectra of the poled copolymer sample do not change. The occurrence of electrical polarization in the absence of orientation dependence of the deuterium line shape indicates molecular reorientation through 180° in the copolymer. View full abstract»

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  • Spin‐on and boat diffusion of Zn into InP and InGaAs grown by metalorganic vapor‐phase epitaxy and liquid‐phase epitaxy

    Page(s): 548 - 552
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    The Zn diffusion into InP and In0.57Ga0.43As was studied. A comparison of three diffusion methods is presented, i.e., boat diffusion, diffusion from As‐ or P‐doped spin‐on films, and diffusion from In‐doped spin‐on films. The diffusion into samples made by different growth methods was investigated, i.e., bulk grown wafers, liquid‐phase epitaxial films (LPE), and metalorganic vapor‐phase epitaxial films (MOVPE). The in‐depth profiles found are from the double diffusion front type, p+ ‐p-‐n. The p+ ‐p- junction position depends on the diffusion method but not significantly on the growth method of the sample, while the p-‐n junction depends on both. For example, with As or P in the spin‐on film, a shallow p+ ‐p- junction and a deep p-‐n junction appear. With In in the spin‐on film, a deep p+ ‐p- junction with a negligibly small p- region is found. Diffusion into bulk and MOVPE samples usually yields deeper p-‐n junctions than into LPE samples. Owing to the fact that in the presented experiments the amount of P, As, In, Ga, or the respective vacancies VP, VAs, VIn, VGa differ, we are able to check which of the existing diffusion models are applicable here. We propose an independent trapping of the mobile interstitially diffusing Zni by two immobile vacancy centers, i.e., Zn on VIn or VGa in the p+ region and Zn on VAsZnVAs or VPZnVP in the p- region. View full abstract»

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  • Interstitial and substitutional Zn in InP and InGaAsP

    Page(s): 553 - 560
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    Closed‐ampoule Zn diffusion in InP results in a net acceptor concentration that is much smaller than the Zn concentration. After subsequent annealing of InP in an atmosphere without Zn, the Zn and net acceptor concentrations have become almost identical, due to a decreased Zn concentration and an increased net acceptor concentration. The annealing treatment gives rise to a decreased contact resistivity. The diffusion depth has not changed. Annealing with a SiN cap on the InP surface does not have this effect on the concentrations. These annealing effects also take place in InGaAsP on InP layers. The results can be explained quantitatively by assuming that Zn is incorporated as both substitutional acceptors and interstitial donors and that only the interstitial Zn is driven out by the annealing, owing to its large diffusion coefficient. Profiles calculated with this interstitial‐substitutional model can be fitted to experimental profiles assuming Zn to diffuse as singly ionized interstitial donors. This model can also describe earlier reported results on Zn diffusion in n‐type InP for which a profile cutoff is found at a depth where the acceptor concentration equals the background donor concentration and in which the acceptor solubility is higher than in undoped InP. View full abstract»

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  • Stability of interfacial oxide layers during silicon wafer bonding

    Page(s): 561 - 563
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    The stability of thin interfacial oxide layers between bonded silicon wafers is investigated experimentally and theoretically. For usual bonding temperatures around 1100 °C and typical times of a few hours, the oxygen diffusivity is not high enough to allow the oxide layer dissolution. For aligned wafers of the same orientation, the oxide layer instead tends to disintegrate in order to minimize the SiO2/Si interface energy. It is possible to stabilize a uniform interfacial oxide layer by rotationally misorienting the two wafers by an angle θ exceeding a critical angle, θ crit, estimated to be between 1° and 5°. View full abstract»

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  • Substrate effect on the deposition of Zn3P2 thin films prepared by a hot‐wall method

    Page(s): 564 - 566
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    Zn3P2 thin films have been deposited by a hot‐wall method on Pyrex glass and (100)GaAs substrates. For GaAs crystalline substrates, higher deposition rates were obtained at the same source and substrate temperatures than those for glass substrates. Layers deposited on (100) GaAs substrates showed stronger preferential (004)orientation of the tetragonal structure, and hence an improved columnar structure is obtained as compared with those on glass substrates. The films having higher crystalline quality deposited on GaAs substrates have room‐temperature resistivities as low as ∼10 Ω cm. View full abstract»

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  • A quantitative study of oxygen behavior during CrSi2 and TiSi2 formation

    Page(s): 567 - 574
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    Oxygen behavior during the formation of CrSi2 and TiSi2 was studied using 16O(α,α)16O resonant scattering and mass dispersive recoil detection analysis. The Ti and Cr films were deposited by e‐beam evaporation in a cryopumped system. The oxygen content in the films was varied by evaporating at different pressures. The silicide films were formed by solid‐solid reaction of the metal layers with the silicon substrate, and the annealing conditions were such that both partly and fully reacted silicides were obtained. The extent of the silicide formation was monitored by backscattering spectrometry. In the case of CrSi2, oxygen was found to be uniformly distributed throughout the silicide layer after annealing. For the Ti/TiSi2 system, however, oxygen seems to have preferentially remained in the Ti layer during the silicide growth, and its final distribution was confined in a region in the silicide close to the surface. It was also observed in the latter case that silicon diffused to the surface at the initial stage of annealing. A model based on the Nernst–Einstein equation is proposed to provide a general explanation for the oxygen behavior in metal/silicon systems. In addition, it was shown that oxygen which was initially in the form of metal oxides and in solid solution had been transformed into SiO2 after the silicide formation. Oxygen loss is observed for all samples, and increases with the extent of annealing. View full abstract»

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  • Plasma deposition of hydrogenated amorphous silicon: Effect of rf power

    Page(s): 575 - 580
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    The experimentally determined growth rate power dependence of plasma‐enhanced chemical‐vapor‐deposited amorphous silicon was compared with the predicted dependence for the case when the SiH3 radicals are the dominant contributors to film growth. The higher experimental growth rate compared to its calculated value can be explained by the influence of Si2H6 produced in the discharge. The maximum of the growth rate was found to be around 50 mW/cm3 . The decrease of the growth rate at powers exceeding 50 mW/cm3 can be explained by the increased influence of hydrogen, which is consistent with the measurements of the refractive index of the deposited films. View full abstract»

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  • Initial epitaxial growth of Cu on Mo{011} by low‐energy electron microscopy and photoemission electron microscopy

    Page(s): 581 - 584
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    Micrographs are published showing the effect of atomic steps, surface defects, and growth conditions on the submonolayer growth of Cu on Mo{011}. Double‐layer growth at various temperatures and multiple‐layer growth are examined. At 700 K Cu nucleates at atomic steps and grows two dimensionally and isotropically out onto the terraces. The first layer is pseudomorphic. A complex double layer grows followed by three‐dimensional islands. At temperatures below 500 K, islands nucleate on the terraces and further growth is monolayer by monolayer on every terrace. Films were grown without any tendency to form three‐dimensional islands. Such films show pronounced quantum‐size effects, which appear as large changes of the reflectivity of the electrons with energy and film thickness. View full abstract»

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Aims & Scope

Journal of Applied Physics is the American Institute of Physics' (AIP) archival journal for significant new results in applied physics

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Editor
P. James Viccaro
Argonne National Laboratory