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21 Sep 1987

Volume 51, Issue 12, pp. 871-950

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Single lobe operation of a 40‐element laser array in an external ring laser cavity

Lew Goldberg and J. F. Weller

Appl. Phys. Lett. 51, 871 (1987); http://dx.doi.org/10.1063/1.98839 (3 pages) | Cited 9 times

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Single lobe operation of a 40‐element GaAlAs gain guided coupled stripe array emitting 500 mW cw is obtained in an external ring laser cavity. The cavity arrangement is equivalent to self‐injection locking of the array by its own output, which is first spatially filtered by a single mode fiber. Diffraction‐limited lobe width of 0.13° and single mode operation are demonstrated with a 90 mW single mode fiber output.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Very low threshold planar buried heterostructure InGaAsP/InP laser diodes prepared by three‐stage metalorganic chemical vapor deposition

H. Ishiguro, T. Kawabata, and S. Koike

Appl. Phys. Lett. 51, 874 (1987); http://dx.doi.org/10.1063/1.98840 (3 pages) | Cited 3 times

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Low threshold InGaAsP/InP lasers with planar buried heterostructure were grown entirely by low‐pressure metalorganic chemical vapor deposition (MOCVD). The threshold current Ith=10 mA and the differential quantum efficiency ηd =60%, which are comparable to lasers grown by liquid phase epitaxy, were obtained. Most lasers randomly selected from one wafer have threshold currents of Ith=10–25 mA, because of high thickness uniformity of MOCVD growth. Stable fundamental transverse mode operation was also obtained up to an output power of 40 mW/facet, due to controlling the active layer width less than 2 μm.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

GaAlAs laser diodes with metalorganic chemical vapor deposition grown ZnSe layer for injection blocking and optical confinement

H. Iwano, Y. Tsunekawa, M. Shimada, T. Takamura, T. Seki, and H. Ohshima

Appl. Phys. Lett. 51, 877 (1987); http://dx.doi.org/10.1063/1.98841 (3 pages) | Cited 4 times

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A transverse mode stabilized GaAlAs laser diode which includes a ZnSe layer for the waveguide has been developed. The double heterostructure of the GaAlAs laser is formed by low‐pressure metalorganic chemical vapor deposition (MOCVD), and a ZnSe layer is grown by adduct‐source MOCVD in order to block the injection current and change the real refractive index in the lateral direction. The fundamental transverse mode oscillation of more than 15 mW is obtained with a low threshold current of 28 mA and a high quantum efficiency of 76%. An output power as high as 25 mW is achieved.
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42.60.By Design of specific laser systems
42.55.Px Semiconductor lasers; laser diodes
42.60.Fc Modulation, tuning, and mode locking
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Characterization of multilayers for extended ultraviolet optics

Félix E. Fernández, Charles M. Falco, P. Dhez, A. Khandar‐Shahabad, L. Névot, B. Pardo, J. Corno, and B. Vidal

Appl. Phys. Lett. 51, 880 (1987); http://dx.doi.org/10.1063/1.98842 (3 pages) | Cited 4 times

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We describe an extensive characterization procedure developed to study multilayers for extended ultraviolet (XUV, 1 Å≲λ≲1000 Å) optics. We present results of this procedure applied to sputtered Si/W multilayers designed as normal‐incidence XUV reflectors for ∼200 Å. Techniques used were low‐angle x‐ray diffraction, Bragg–Brentano and Seemann–Bohlin diffraction, wide‐film Debye–Scherrer (Read) camera, Rutherford backscattering spectroscopy, and transmission electron microscopy. Reflectances at several incidence angles were measured with synchrotron radiation and found to agree very well with reflectance curves calculated without adjustable parameters. The information obtained from the different techniques forms a coherent picture of the structure of these materials.
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78.66.-w Optical properties of specific thin films
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
68.55.-a Thin film structure and morphology
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
42.79.-e Optical elements, devices, and systems

Effect of Ne and Ar on the performance of a high‐pressure ArF∗ laser pumped by a small coaxial electron beam

P. J. M. Peters, I. H. T. Fierkens, and W. J. Witteman

Appl. Phys. Lett. 51, 883 (1987); http://dx.doi.org/10.1063/1.98843 (3 pages) | Cited 4 times

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Optimizations of the F2/Ar/Ne gas composition and the optical cavity configuration were performed for an ArF∗ laser in the pressure range from 1 to 14 bar. The excitation source was a coaxial electron beam with a pulse length of 40 ns. From an active volume of 16 cm3 a maximum output energy of 130 mJ at a total gas pressure of 14 bar was obtained when Ne was used as the buffer gas.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.55.-f Lasers

GaAs‐GaAlAs graded‐index separate confinement heterostructure laser diodes selectively grown by molecular beam epitaxy on SiO2‐masked substrates

J. M. Hong, M. C. Wu, S. Wang, W. I. Wang, and L. L. Chang

Appl. Phys. Lett. 51, 886 (1987); http://dx.doi.org/10.1063/1.98844 (3 pages) | Cited 3 times

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The GaAs‐GaAlAs graded‐index separate confinement heterostructure was grown selectively by molecular beam epitaxy on a SiO2‐masked GaAs (100) substrate. The stripe windows on the SiO2 mask were 10 μm in width and were oriented along [011] direction. The laser diodes thus fabricated lased in a single longitudinal mode with a side mode suppression ratio of 95:1. Both the longitudinal mode and the single‐lobe far‐field pattern were stable up to 4Ith.
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42.55.Px Semiconductor lasers; laser diodes
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Fc Modulation, tuning, and mode locking

Photorefractive properties of doped cadmium telluride

R. B. Bylsma, P. M. Bridenbaugh, D. H. Olson, and A. M. Glass

Appl. Phys. Lett. 51, 889 (1987); http://dx.doi.org/10.1063/1.98845 (3 pages) | Cited 55 times

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The first study of the photorefractive properties of doped CdTe has demonstrated high sensitivity for optical processing applications. Of the binary II‐VI and III‐V semiconductors, CdTe has the highest electro‐optic coefficient r41 in the infrared, some three times larger than that of GaAs and InP. Deep levels introduced into CdTe exhibit appropriate absorption and photoconductivity at 1.06 μm by doping with V and Ti impurities. Photorefractive beam coupling experiments in CdTe:V gave small signal gains of 0.7 cm−1, and diffraction efficiencies with no applied electrical field of 0.7%. Thus, CdTe appears to be superior to previously studied III‐V semiconductors, in the near‐infrared spectrum. Optimization of doping and trap densities is expected to result in gain which exceeds the absorption loss, thereby allowing phase conjugation with infrared injection lasers.
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78.20.Jq Electro-optical effects
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.79.Vb Optical storage systems, optical disks

Standing light wave in front of a silver mirror investigated by photothermal spectroscopy

Wolfgang Knoll and Hans J. Coufal

Appl. Phys. Lett. 51, 892 (1987); http://dx.doi.org/10.1063/1.98846 (3 pages) | Cited 4 times

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Photothermal spectra of an isocyanine dye monolayer, separated from a silver mirror by a varying number of cadmium arachidate layers, are recorded with a pyroelectric calorimeter. The spatial dependence of the light intensity in front of the silver mirror is observed. The phase angle of a light wave upon reflection from the silver surface is determined to be 124±5° at a wavelength of 578 nm. The quantum yield for radiationless deexcitation at that wavelength is found to be 33±7%.
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42.15.Dp Wave fronts and ray tracing
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.25.Lc Birefringence

Multistable mode locking of InGaAsP semiconductor lasers

M. Kuznetsov, D. Z. Tsang, J. N. Walpole, Z. L. Liau, and E. P. Ippen

Appl. Phys. Lett. 51, 895 (1987); http://dx.doi.org/10.1063/1.98847 (3 pages) | Cited 7 times

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We have investigated the pulsation behavior of InGaAsP semiconductor lasers with a proton‐bombarded segment. These lasers emit picosecond (30–70 ps) pulses at gigahertz (0.6–3.0 GHz) rates. An antireflection‐coated diode in an external cavity is passively mode locked and multistable; as many as four co‐existing states are observed. Interlocking hysteresis loops are observed in the pulsation frequency, pulse width, and output power as functions of the bias current. A delayed feedback model explains qualitative features of the multistable mode locking. To our knowledge this is the first report of multistability of laser pulsation.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes
42.65.Pc Optical bistability, multistability, and switching, including local field effects

Detection of Cl and chlorine‐containing negative ions in rf plasmas by two‐photon laser‐induced fluorescence

Gary S. Selwyn, L. D. Baston, and H. H. Sawin

Appl. Phys. Lett. 51, 898 (1987); http://dx.doi.org/10.1063/1.98848 (3 pages) | Cited 28 times

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Chlorine atoms have been detected in rf etching plasmas of CClF3 and CCl2F2 with three‐dimensional spatial resolution using a two‐photon laser‐induced fluorescence technique. The spin‐forbidden 4p(4S0)–3p(2P0) transition is pumped by absorption of two 233.3‐nm laser photons. Decay of the excited state results in 725–775 nm emission. Spatially resolved plasma concentration measurements under certain etching conditions indicate an anomalously large signal spike at the plasma/sheath boundary, an effect attributed to an aggregation of chlorine‐containing negative ions which are also detected by this technique. The negative ions are detected by laser‐induced photodetachment followed by two‐photon excitation of atomic Cl.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
32.50.+d Fluorescence, phosphorescence (including quenching)
33.50.-j Fluorescence and phosphorescence; radiationless transitions, quenching (intersystem crossing, internal conversion)
81.65.-b Surface treatments

Intensity oscillations in reflection high‐energy electron diffraction during molecular beam epitaxy of Ni on W(110)

C. Koziol, G. Lilienkamp, and E. Bauer

Appl. Phys. Lett. 51, 901 (1987); http://dx.doi.org/10.1063/1.98795 (3 pages) | Cited 30 times

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Reflection high‐energy electron diffraction intensities during molecular beam epitaxy growth of Ni on W(110) were studied. The damping and polar angle dependence of the observed oscillations are discussed. Intensity oscillations during preparation of a Ni/Cu superlattice are also reported.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.05.jh Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED)
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.55.-a Thin film structure and morphology

Thermal donor formation in silicon: A new kinetic model based on self‐interstitial aggregation

D. Mathiot

Appl. Phys. Lett. 51, 904 (1987); http://dx.doi.org/10.1063/1.98796 (3 pages) | Cited 22 times

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A new kinetic model is presented for the formation of thermal donors near 450 °C in oxygen‐rich silicon. This model is based on the aggregation of the self‐interstitials generated by the early stage of oxygen precipitation. Good agreement is obtained with published experimental kinetics, and the model is able to account for several other observations, such as the influence of carbon.
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61.72.Bb Theories and models of crystal defects
61.72.jd Vacancies
61.72.jj Interstitials
61.72.Yx Interaction between different crystal defects; gettering effect
66.30.Lw Diffusion of other defects

Ion‐chain interaction in keV ion‐beam‐irradiated polystyrene

L. Calcagno, G. Foti, A. Licciardello, and O. Puglisi

Appl. Phys. Lett. 51, 907 (1987); http://dx.doi.org/10.1063/1.98797 (3 pages) | Cited 16 times

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Molecular weight distribution has been measured in monodisperse polystyrene film (MW=9 000 amu) after ion bombardment, in the ion fluence range 1011–1013 ions/cm2. The chosen beams are 100 keV He, 200 keV Ne, and 400 keV Ar. The experimental data have been interpreted in terms of a simple statistical model for cross‐links. The chemical yield is found to be very high and equal to 0.30, about a factor of 10 higher than the values given in the literature for gamma irradiation [M. Dole, in The Radiation Chemistry of Macromolecules (Academic, New York, 1973), Vol. 2, Chap. 5, p. 57].
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36.20.Cw Molecular weights, dispersity
61.80.Jh Ion radiation effects

Structural and photoluminescent properties of GaInAs quantum wells with InP barriers grown by organometallic vapor phase epitaxy

K. W. Carey, R. Hull, J. E. Fouquet, F. G. Kellert, and G. R. Trott

Appl. Phys. Lett. 51, 910 (1987); http://dx.doi.org/10.1063/1.98798 (3 pages) | Cited 22 times

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Ga0.47In.53As/InP quantum well structures grown by atmospheric pressure organometallic vapor phase epitaxy are characterized by high‐resolution transmission electron microscopy (HRTEM) and 4 K photoluminescence (PL). Microdensitometer analysis of the HRTEM images shows GaInAs wells as narrow as 10 Å with slightly asymmetric interface widths. The InP to GaInAs transitions occur within 200 monolayers while the GaInAs to InP transitions are 3–5 monolayers wide, probably due to As carryover. 4 K PL shows half‐widths below 9 meV for quantization shifts up to 140 meV. PL peak shifts as large as 395 meV for the narrowest quantum wells are observed compared to bulk Ga0.47In0.53As.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.55.Cr III-V semiconductors
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.55.-a Thin film structure and morphology

Organic electroluminescent diodes

C. W. Tang and S. A. VanSlyke

Appl. Phys. Lett. 51, 913 (1987); http://dx.doi.org/10.1063/1.98799 (3 pages) | Cited 4645 times

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A novel electroluminescent device is constructed using organic materials as the emitting elements. The diode has a double‐layer structure of organic thin films, prepared by vapor deposition. Efficient injection of holes and electrons is provided from an indium‐tin‐oxide anode and an alloyed Mg:Ag cathode. Electron‐hole recombination and green electroluminescent emission are confined near the organic interface region. High external quantum efficiency (1% photon/electron), luminous efficiency (1.5 lm/W), and brightness (>1000 cd/m2) are achievable at a driving voltage below 10 V.
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85.60.Jb Light-emitting devices
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.61.Cw Elemental semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors
78.60.Fi Electroluminescence

Rapid thermal annealing of Si‐implanted GaAs with trimethylarsenic overpressure

S. Reynolds, D. W. Vook, W. G. Opyd, and J. F. Gibbons

Appl. Phys. Lett. 51, 916 (1987); http://dx.doi.org/10.1063/1.98800 (3 pages) | Cited 20 times

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We have developed a novel rapid thermal processor to perform annealing of ion‐implanted GaAs in a trimethylarsenic overpressure. This has allowed study of arsenic ambient annealing in a time/temperature regime not accessible with an arsine furnace. We have compared Si implant activation efficiency and surface degradation for arsenic ambient and proximity capped anneals. The arsenic ambient gives consistently higher activation efficiency with better surfaces.
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81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
81.40.Rs Electrical and magnetic properties related to treatment conditions
61.72.U- Doping and impurity implantation
72.80.Ey III-V and II-VI semiconductors

Study of thermally oxidized yttrium films on silicon

M. Gurvitch, L. Manchanda, and J. M. Gibson

Appl. Phys. Lett. 51, 919 (1987); http://dx.doi.org/10.1063/1.98801 (3 pages) | Cited 71 times

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Electrical and structural characteristics of thin thermally oxidized yttrium layers on Si and on Si covered with 40 Å of SiO2 have been investigated. The factor of ∼ four advantage in the dielectric constant of Y2O3 over SiO2, coupled with extremely low leakage current density of better than 10−10 A/cm2 in a field of 1.9 MV/cm, sufficiently high breakdown strength, and well‐behaved capacitance‐voltage characteristics makes Y2O3 a viable candidate for Si very large scale integration applications, at least in passive devices. High‐resolution transmission electron microscopy reveals the structure of the composite dielectric and provides good agreement between calculated and experimental capacitance.
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73.61.Ng Insulators
68.55.-a Thin film structure and morphology
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
85.40.Bh Computer-aided design of microcircuits; layout and modeling

Incorporation of boron during thermal chemical vapor deposition of doped hydrogenated amorphous silicon

Howard M. Branz, John H. Flint, Christopher J. Harris, John S. Haggerty, and David Adler

Appl. Phys. Lett. 51, 922 (1987); http://dx.doi.org/10.1063/1.98802 (3 pages) | Cited 1 time

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We report investigations of B incorporation during the growth of B‐doped hydrogenated amorphous silicon (a‐Si:H) thin films by laser‐induced chemical vapor deposition (CVD) from mixtures of SiH4 and B2H6. Because B2H6 decomposition is very rapid, nearly all the B admitted into the reaction cell is incorporated in the growing film and the B concentration in the solid is B2H6 flow rate limited rather than controlled by the gas phase dopant concentration. Widely varying B‐incorporation efficiencies reported for B‐doped a‐Si:H grown by a variety of thermal CVD techniques are summarized and explained.
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68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.-a Thin film structure and morphology

Monte Carlo algorithm for generation‐recombination noise in semiconductors

Lino Reggiani, Paolo Lugli, and Vladimir Mitin

Appl. Phys. Lett. 51, 925 (1987); http://dx.doi.org/10.1063/1.98803 (3 pages) | Cited 18 times

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We present an original Monte Carlo procedure to account for generation‐recombination noise through impurity centers in semiconductors. Numerical calculations are specialized to the case of holes in Si at 77 K. Results are found to compare favorably with available experiments.
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72.70.+m Noise processes and phenomena
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.10.Fk Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect)

Growth of CdZnTe on Si by low‐pressure chemical vapor deposition

Jitendra S. Goela and Raymond L. Taylor

Appl. Phys. Lett. 51, 928 (1987); http://dx.doi.org/10.1063/1.98804 (3 pages) | Cited 10 times

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Epitaxial layers of Cd1−xZnxTe (0.04≤x≤0.62) have been grown on (100) and (111) silicon substrates by a low‐pressure chemical vapor deposition (LPCVD) process. Elemental metals were used as sources of cadmium and zinc and dimethyltelluride was used as a source of tellurium. The characterization of layers by x‐ray diffraction, scanning electron microscope, and scanning electron microscope x‐ray dispersive analysis shows that hot wall LPCVD is a viable technique to grow large‐area epitaxial layers of CdZnTe on different substrates.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)

CdTe metal‐semiconductor field‐effect transistors

D. L. Dreifus, R. M. Kolbas, K. A. Harris, R. N. Bicknell, R. L. Harper, and J. F. Schetzina

Appl. Phys. Lett. 51, 931 (1987); http://dx.doi.org/10.1063/1.98805 (3 pages) | Cited 15 times

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We report the first demonstration of CdTe metal‐semiconductor field‐effect transistors. These transistors were fabricated using n‐type CdTe films grown by photoassisted molecular beam epitaxy. Using this new film deposition technique, it is possible to obtain highly activated n‐type or p‐type films suitable for device applications. In the present work, transistor structures with 5 or 100 μm gate lengths having channel dopings in the range from 2×1016 to 2×1017 cm−3 were fabricated and tested. The 5 μm gate devices have transconductances as large as 10 mS/mm and pinch‐off voltages of 4.0 V.
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85.30.Tv Field effect devices
73.61.Ga II-VI semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.15.Jj Ion and electron beam-assisted deposition; ion plating

Quantum well avalanche multiplication initiated by 10 μm intersubband absorption and photoexcited tunneling

B. F. Levine, K. K. Choi, C. G. Bethea, J. Walker, and R. J. Malik

Appl. Phys. Lett. 51, 934 (1987); http://dx.doi.org/10.1063/1.98806 (3 pages) | Cited 50 times

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We have achieved avalanche gain at a wavelength of 10.3 μm in AlxGa1−xAs/GaAs quantum well superlattices. The photoelectrons are generated by resonant intersubband absorption and tunneling, and then avalanche via hot‐electron impact ionization of carriers out of the quantum wells. Good agreement is obtained between a theoretical calculation of this process and our experiments.
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73.40.Ty Semiconductor-insulator-semiconductor structures
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
73.50.Pz Photoconduction and photovoltaic effects
73.61.Ey III-V semiconductors

Identification of residual donors in high‐purity epitaxial GaAs by magnetophotoluminescence

S. S. Bose, B. Lee, M. H. Kim, and G. E. Stillman

Appl. Phys. Lett. 51, 937 (1987); http://dx.doi.org/10.1063/1.98807 (3 pages) | Cited 17 times

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Show Abstract
The magnetophotoluminescence peaks in the ‘‘two‐electron’’ satellites of the donor bound exciton transitions corresponding to the shallow donors S, Si, Ge, Sn, and Te have been identified by correlation of photoluminescence measurements with photothermal ionization measurements on the same high‐purity epitaxial GaAs samples. The magnetophotoluminescence measurements were made at 1.7 K and a magnetic field of 9.0 T. These results permit the use of magnetophotoluminescence measurements for the identification of residual donor impurity species in high‐purity GaAs.
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78.20.Ls Magneto-optical effects
78.55.Cr III-V semiconductors
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Microstructure and properties of YBa2Cu3O9−δ superconductors with transitions at 90 and near 290 K

J. Narayan, V. N. Shukla, S. J. Lukasiewicz, N. Biunno, R. Singh, A. F. Schreiner, and S. J. Pennycook

Appl. Phys. Lett. 51, 940 (1987); http://dx.doi.org/10.1063/1.98808 (3 pages) | Cited 32 times

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We have investigated the microstructure and properties of YBa2Cu3O9−δ that contain resistive transitions at 90 and near 290 K using high‐resolution and analytical transmission electron microscopy and Raman scattering techniques. The specimens contain normal orthorhombic (Pmmm space group) phase associated with Tc=90 K, and another phase which we tentatively assign it to be associated with the resistive transitions near 290 K. The new phase has a c axis larger by about 16% and it grows epitaxially on the {100} planes of the orthorhombic (tripled perovskite unit cell) phase having Tc=90 K.
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74.10.+v Occurrence, potential candidates
81.30.-t Phase diagrams and microstructures developed by solidification and solid-solid phase transformations
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination

Fabrication of dense Ba2YCu3O7−δ superconductor wire by molten oxide processing

S. Jin, T. H. Tiefel, R. C. Sherwood, G. W. Kammlott, and S. M. Zahurak

Appl. Phys. Lett. 51, 943 (1987); http://dx.doi.org/10.1063/1.98809 (3 pages) | Cited 48 times

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Fabrication of high Tc ceramic superconductors by an oxide melting method in place of a conventional sintering method has been attempted. Using three different processes, i.e., melt drawing, melt spinning, or preform‐wire melting, it is demonstrated that the Ba2YCu3O7−δ type superconductors can successfully be fabricated into a desired geometry such as wire and ribbon. Tc’s for R=0 were about 92 K. The density of the melt‐processed compound was measured to be as high as 6.2 g/cm3, or ∼98% of the theoretical density 6.3 g/cm3 as compared to the value of 80–85% density for sintered samples. The increased density is likely to be responsible for the noted improvements in fracture resistance and in the Jc value of the melt‐processed compound.
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81.10.Fq Growth from melts; zone melting and refining
74.70.-b Superconducting materials other than cuprates
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