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14 Sep 1987

Volume 51, Issue 11, pp. 783-866

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Total internal diffraction of plasmon surface polaritons

Benno Rothenhäusler and Wolfgang Knoll

Appl. Phys. Lett. 51, 783 (1987); http://dx.doi.org/10.1063/1.98865 (3 pages) | Cited 18 times

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Total internal diffraction of plasmon surface polariton fields by a dielectric phase grating is described. The grating was fabricated by partly desorbing thin organic multilayers deposited on top of the plasmon‐carrying Ag‐air interface through the regularly spaced holes of an electron microscope grid. The diffraction pattern shows for various angles of incidence a characteristic intensity distribution which can be understood taking into account a grating wave vector mediated coupling of the two plasmons corresponding to the two different layer structures.
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73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.66.Qn Polymers; organic compounds
42.79.Dj Gratings
42.25.Dd Wave propagation in random media
42.25.Fx Diffraction and scattering
42.25.Ja Polarization

Laser‐frequency mixing in the junction of a scanning tunneling microscope

L. Arnold, W. Krieger, and H. Walther

Appl. Phys. Lett. 51, 786 (1987); http://dx.doi.org/10.1063/1.98866 (3 pages) | Cited 15 times

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The frequency response and the frequency‐mixing properties of the tunneling junction of a scanning tunneling microscope (STM) were investigated using the radiation of two CO2 lasers. Difference frequencies of up to 90 MHz were detected over a wide range of bias voltages and tunneling currents. At tunneling currents typical of STM operation the beat signal decreases as the bias voltage is increased. However, this dependence is reversed at higher tunneling currents, where the STM begins to resemble a point‐contact metal‐insulator‐metal diode. For low tunneling currents the generation of the beat signal is attributed mainly to thermally assisted tunneling.
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07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination
73.40.Gk Tunneling
73.40.Rw Metal-insulator-metal structures
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Scattering in low‐loss GaAs/AlGaAs rib waveguides

R. J. Deri, E. Kapon, and L. M. Schiavone

Appl. Phys. Lett. 51, 789 (1987); http://dx.doi.org/10.1063/1.98867 (3 pages) | Cited 17 times

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Single‐mode rib waveguides with low propagation loss (0.2 dB/cm) were fabricated on GaAs/AlGaAs single heterostructures by dry etching. The attenuation of these guides was measured to study the effect of rib structure on propagation loss at 1.52 μm. An increase in loss with increased rib height and decreased rib width was associated with scattering due to a rib surface roughness of approximately 50 nm for ion milled waveguides. Fabrication with reactive ion etching reduced the rib roughness and its associated scattering loss by a factor of 3 or more in waveguides with strong optical confinement (effective index difference of 0.012) of the fundamental guided mode.
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42.79.Gn Optical waveguides and couplers
42.82.-m Integrated optics
78.30.Fs III-V and II-VI semiconductors
81.65.-b Surface treatments

Design of optimized high‐speed depletion‐edge‐translation optical waveguide modulators in III‐V semiconductors

L. A. Coldren, J. G. Mendoza‐Alvarez, and R. H. Yan

Appl. Phys. Lett. 51, 792 (1987); http://dx.doi.org/10.1063/1.98868 (3 pages) | Cited 10 times

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See Also: Erratum

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A new first‐principle theory that includes the higher order field and carrier effects in semiconductor waveguide refractive index modulators has been developed. For the first time, the relative importance of the electrorefractive, band filling, linear electro‐optic, and plasma effects is shown. The theory agrees well with measurements from experimental AlGaAs/GaAs depletion‐edge‐translation (DET) phase modulators that have given record levels of phase shift per volt per unit length, and it suggests an improved DET device design with much larger phase shifting efficiency. The required drive voltage/bandwidth figure of merit, Vπ/ Δf, for this configuration (without including quantum wells) is lower than for any other existing optical index modulator.
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42.79.Hp Optical processors, correlators, and modulators
42.79.Gn Optical waveguides and couplers
85.30.De Semiconductor-device characterization, design, and modeling
85.60.-q Optoelectronic devices

Observation of periodical short pulse trains in free‐electron laser oscillations

Y. Kawamura, K. Toyoda, and M. Kawai

Appl. Phys. Lett. 51, 795 (1987); http://dx.doi.org/10.1063/1.98869 (3 pages) | Cited 5 times

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Periodical short pulse trains were observed in a long pulse, low current, low voltage waveguide mode free‐electron laser. The pulse width and the pulse train intervals of the periodical short pulse trains were about a few ns and about 23 ns, respectively. These pulse trains can be explained as self‐mode‐locked oscillations of a free‐electron laser.
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41.60.Cr Free-electron lasers
42.60.Fc Modulation, tuning, and mode locking
42.55.Px Semiconductor lasers; laser diodes
42.55.Rz Doped-insulator lasers and other solid state lasers

Control of hydrogen content of boron thin films produced in a dc toroidal discharge

H. Toyoda, H. Sugai, T. Isozumi, and T. Okuda

Appl. Phys. Lett. 51, 798 (1987); http://dx.doi.org/10.1063/1.98870 (3 pages) | Cited 12 times

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Hydrogenated amorphous boron films have been produced by a toroidal glow discharge of B2H6/He mixtures at low pressures (10−2 Torr). Chemically stable pure films with a low hydrogen content can be formed at a moderate substrate temperature (∼200 °C) when the diborane flow rate is raised above 10 sccm with the discharge power lowered below 100 W. The controllability of H content is potentially interesting for applications in the coating of nuclear fusion devices, as well as for use in electronic devices.
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68.55.Nq Composition and phase identification
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
28.52.-s Fusion reactors

Dislocation bundle formation during liquid encapsulated Czochralski growth of GaAs crystals

Haruhiko Ono and Junji Matsui

Appl. Phys. Lett. 51, 801 (1987); http://dx.doi.org/10.1063/1.99007 (3 pages) | Cited 5 times

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Residual dislocations in a P‐alloyed and an undoped GaAs crystal grown by the liquid encapsulated Czochralski method were investigated by transmission electron microscopy. In the undoped GaAs, dislocation bundles constructing cell walls and/or lineages consist of at least three different Burgers vectors. In the P‐alloyed GaAs with low dislocation density, individual dislocation reactions were observed. Sessile dislocations were found to be formed by an interaction between two kinds of dislocations. The sessile dislocation formation may be a first step for the complicated dislocation structure in the undoped crystal.
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61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination

High‐quality amorphous silicon germanium produced by catalytic chemical vapor deposition

Hideki Matsumura

Appl. Phys. Lett. 51, 804 (1987); http://dx.doi.org/10.1063/1.98871 (2 pages) | Cited 35 times

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High‐quality amorphous silicon germanium (a‐SiGe:H) films are produced by a new ‘‘catalytic chemical vapor deposition (CTL CVD)’’ method. In the method, a SiH4, GeH4, and H2 gas mixture is decomposed without using any plasmas or photochemical excitation, but using only the thermal or the catalytic reaction with a heated tungsten catalyzer. Photoconductive properties of CTL CVD a‐SiGe:H are apparently not degraded as the Ge content increases. The photoconductivity and the photosensitivity for AM‐1 of 100 mW/cm2 are 10−5–10−4 (Ω cm)−1 and 104, respectively, even for the sample of optical band gap of 1.40–1.45 eV.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
73.50.Pz Photoconduction and photovoltaic effects
73.61.Cw Elemental semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors

Characterization of a thin Si‐implanted and rapid thermal annealed n‐GaAs layer

Suehiro Sugitani, Kimiyoshi Yamasaki, and Hajime Yamazaki

Appl. Phys. Lett. 51, 806 (1987); http://dx.doi.org/10.1063/1.98872 (3 pages) | Cited 15 times

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Very thin, high carrier concentration layers for high performance GaAs field‐effect transistors are realized by lamp annealing, combined with low‐energy (<30 keV) ion implantation. The characteristics of these thin layers are investigated by the Hall effect, capacitance‐voltage, photoluminescence, and secondary ion mass spectrometry (SIMS). The optimum temperature giving the maximum sheet carrier concentration is the result of a balance between damage recovery and acceptor generation. The optimum temperature decreases as the implantation energy is reduced. The effective implanted layer thicknesses obtained by SIMS are larger than the Lindhard–Scharff–Schiott calculated values. The minimum effective active layer thickness of 0.045 μm is obtained with a 10‐keV implanted sample. This value is about one‐half that obtained for the 30‐keV implanted furnace annealed sample.
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73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.61.Ey III-V semiconductors
85.30.Tv Field effect devices
81.40.Rs Electrical and magnetic properties related to treatment conditions

Structural and compositional integrity of lattice‐matched ZnSe0.95S0.05 on (100) orientated GaAs

Heather M. Yates and John O. Williams

Appl. Phys. Lett. 51, 809 (1987); http://dx.doi.org/10.1063/1.98873 (2 pages) | Cited 7 times

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Lattice‐matched ZnSe0.95S0.05 epitaxial layers have been grown on (100) oriented GaAs substrates by atmospheric pressure metalorganic vapor phase epitaxy. Blue room‐temperature photoluminescence is observed and the interface is both compositionally and structurally abrupt as shown by secondary ion mass spectrometry and high‐resolution transmission electron microscopy.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.-a Thin film structure and morphology
81.15.Kk Vapor phase epitaxy; growth from vapor phase
78.55.Cr III-V semiconductors

Tunnel spectroscopy using titanium metal barriers on p−‐Si/p+‐Si molecular beam epitaxial films

W. Cabanski, M. Schulz, E. Kasper, and H. J. Herzog

Appl. Phys. Lett. 51, 811 (1987); http://dx.doi.org/10.1063/1.98874 (3 pages) | Cited 1 time

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Tunnel spectroscopy is employed to analyze electronic and vibrational excitations in Ti/p−‐Si/p+‐Si structures. The thin p−‐Si layer of about 70 Å thickness was grown by molecular beam epitaxy (MBE). The second derivative of the tunneling current through the Ti/p−‐Si Schottky barrier is measured at a temperature T=8 K. A series of peaks is observed in the voltage range 0 to ±80 mV. The observed structure is interpreted by inelastic tunneling via phonons. Impurity states of Ga‐x(E−Ev=57 meV), Ga+(E−Ev=2 meV), B(E−Ev=46 meV), and B‐x(E−Ev=37 meV) in Si can be resolved at the interface of the MBE films. The method may be also useful to analyze interface states at the metal‐semiconductor interface.
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73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.Gk Tunneling
73.40.Ns Metal-nonmetal contacts
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Growth and characterization of molecular beam epitaxial GaAs layers on porous silicon

T. L. Lin, L. Sadwick, K. L. Wang, Y. C. Kao, R. Hull, C. W. Nieh, D. N. Jamieson, and J. K. Liu

Appl. Phys. Lett. 51, 814 (1987); http://dx.doi.org/10.1063/1.98821 (3 pages) | Cited 19 times

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GaAs layers have been grown on porous silicon (PS) substrates with good crystallinity by molecular beam epitaxy. In spite of the surface irregularity of PS substrates, no surface morphology deterioration was observed on epitaxial GaAs overlayers. A 10% Rutherford backscattering spectroscopy minimum channeling yield for GaAs‐on‐PS layers as compared to 16% for GaAs‐on‐Si layers grown under the same condition indicates a possible improvement of crystallinity when GaAs is grown on PS. Transmission electron microscopy reveals that the dominant defects in the GaAs‐on‐PS layers are microtwins and stacking faults, which originate from the GaAs/PS interface. GaAs is found to penetrate into the PS layers. n‐type GaAs/p‐type PS heterojunction diodes were fabricated with good rectifying characteristics.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
85.30.De Semiconductor-device characterization, design, and modeling
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics

Perpendicular electronic transport in doping superlattices

E. F. Schubert, J. E. Cunningham, and W. T. Tsang

Appl. Phys. Lett. 51, 817 (1987); http://dx.doi.org/10.1063/1.98822 (3 pages) | Cited 26 times

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Electronic transport measurements are performed at 77 and 300 K on doping superlattices in perpendicular direction to the quantum well planes. The periods of the doping superlattices range from 150 to 600 Å. The current‐voltage characteristics in long period doping superlattices (type B) are strongly nonlinear and exhibit a new type of negative differential conductivity. The occurrence of negative differential conductivity is caused by avalanche multiplication in the high‐field regions of the superlattice and accumulation of holes in the valence‐band maxima. In short period doping superlattices (type A) the current‐voltage characteristics are linear at temperatures of 300 and 77 K showing that tunneling through thin barriers dominates perpendicular transport. The calculation of the tunneling current yields a strong dependence on the period (exp−z3/2p).
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73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Ey III-V semiconductors
73.40.Gk Tunneling
73.50.-h Electronic transport phenomena in thin films

High‐fluence ion damage effects in Ar‐implanted (InGa)As/GaAs strained‐layer superlattices

D. R. Myers, G. W. Arnold, C. R. Hills, L. R. Dawson, and B. L. Doyle

Appl. Phys. Lett. 51, 820 (1987); http://dx.doi.org/10.1063/1.98823 (3 pages) | Cited 6 times

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We have characterized (InGa)As/GaAs strained‐layer superlattices (SLS’s) that have been implanted with 300 keV argon ions at room temperature for fluences sufficient to induce precipitous stress relief in the implanted composite. SLS compositional modulation is lost due to ion beam mixing over much of the ion range; however, the implanted regions remain crystalline despite extensive damage near the mean ion range. High‐density dislocation networks are found near the substrate‐buffer interface after precipitous stress relief and are correlated with the occurrence of the effect.
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61.80.Jh Ion radiation effects
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.60.Bs Mechanical and acoustical properties

Improved β‐SiC heteroepitaxial films using off‐axis Si substrates

J. A. Powell, L. G. Matus, M. A. Kuczmarski, C. M. Chorey, T. T. Cheng, and P. Pirouz

Appl. Phys. Lett. 51, 823 (1987); http://dx.doi.org/10.1063/1.98824 (3 pages) | Cited 29 times

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All β‐SiC films grown using on‐axis (001) Si substrates that have been examined with transmission electron microscopy exhibit a high density of interfacial twins, stacking faults, and antiphase disorder. The antiphase boundaries can be decorated by chemical etching, sputter etching, wet oxidation, and β‐SiC growth in the presence of diborane. All traces of antiphase disorder are eliminated when the heteroepitaxial growth is carried out on vicinal (001) Si substrates that are tilted 2° about a 〈110〉 axis. In addition, growth on the off‐axis Si produces β‐SiC films that are significantly smoother than on‐axis films. The density of stacking faults is apparently unaffected by growth on the off‐axis substrates.
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68.35.Dv Composition, segregation; defects and impurities
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)

Chemical beam epitaxially grown InP/InGaAsP interference mirror for use near 1.55 μm wavelength

K. Tai, S. L. McCall, S. N. G. Chu, and W. T. Tsang

Appl. Phys. Lett. 51, 826 (1987); http://dx.doi.org/10.1063/1.98825 (2 pages) | Cited 19 times

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An interference mirror for use near 1.55 μm wavelength was constructed using InP and lattice‐matched InGaAsP on an InP substrate with chemical beam epitaxy methods. The maximum reflectivity was 92.5% at 1.46 μm. The design value was 94.75% at 1.55 μm. The mirror was used as an output mirror in a synchronously pumped mode‐locked Tl:KCl color center laser.
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42.15.Eq Optical system design
42.79.Bh Lenses, prisms and mirrors
42.60.By Design of specific laser systems
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors

Dynamics of exciton transfer between monolayer‐flat islands in single quantum wells

Benoit Deveaud, T. C. Damen, Jagdeep Shah, and C. W. Tu

Appl. Phys. Lett. 51, 828 (1987); http://dx.doi.org/10.1063/1.98826 (3 pages) | Cited 59 times

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We have studied the transfer dynamics of excitons between large, monolayer‐flat islands in single quantum wells, using subpicosecond luminescence spectroscopy. We show that the excitons transfer from the narrow to the wide regions of the well in ∼250 ps.
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73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.55.Cr III-V semiconductors
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
73.61.Ey III-V semiconductors

Doping superlattices grown in channeled GaAs substrates by molecular beam epitaxy through a built‐in shadow mask

G. Hasnain, D. Mars, G. H. Döhler, M. Ogura, and J. S. Smith

Appl. Phys. Lett. 51, 831 (1987); http://dx.doi.org/10.1063/1.98827 (3 pages) | Cited 7 times

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Micron width doping superlattices or n‐i‐p‐i structures with grown‐in interdigital highly selective contacts are grown successfully in a channeled GaAs substrate by molecular beam epitaxy (MBE) through a built‐in shadow mask. Excellent diode characteristics and efficient lateral injection electroluminescence demonstrate the high quality of the masked MBE growth in the channeled substrate.
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68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
85.30.De Semiconductor-device characterization, design, and modeling
78.60.Fi Electroluminescence

Fe acceptor level in In1−xGaxAsyP1−y/InP

M. Sugawara, M. Kondo, T. Takanohashi, and K. Nakajima

Appl. Phys. Lett. 51, 834 (1987); http://dx.doi.org/10.1063/1.98828 (3 pages) | Cited 10 times

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The Fe acceptor level in In1−xGaxAsyP1−y lattice matched to InP (x=0.47y) is investigated employing current‐voltage characteristics and deep level transient spectroscopy. The activation energy decreases as the proportion of arsenic, y, increases. However, considering the band‐edge discontinuity in this material, it was found that the Fe acceptor level is aligned at a constant energy. This is in excellent agreement with the vacuum referred binding energy model.
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73.20.Hb Impurity and defect levels; energy states of adsorbed species
73.61.Ey III-V semiconductors

Molecular beam epitaxial growth of III‐V compound semiconductor in the presence of a low‐energy ion beam: A Monte Carlo simulation study

S. B. Ogale, A. Madhukar, and M. Thomsen

Appl. Phys. Lett. 51, 837 (1987); http://dx.doi.org/10.1063/1.98829 (3 pages) | Cited 9 times

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Monte Carlo simulation study of molecular beam epitaxial growth of III‐V compound semiconductor in the presence of a low‐energy ion beam is performed to examine the role of such physical parameters as beam induced preferential desorption and enhanced surface migration on the growth front morphology. It is demonstrated that the smoothness of the growth front can be controlled by appropriate choice of ion type, its energy, angle of incidence, and flux. Thus smooth morphology can be realized at temperatures significantly lower than normal epitaxial growth temperatures.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.-a Thin film structure and morphology
66.30.J- Diffusion of impurities
61.80.Jh Ion radiation effects

Tunneling and transverse wave vector conservation in GaAs/AlGaAs heterostructures

John A. Lebens, Robert H. Silsbee, and Steven L. Wright

Appl. Phys. Lett. 51, 840 (1987); http://dx.doi.org/10.1063/1.98830 (3 pages) | Cited 11 times

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We have studied transverse wave vector conservation in the tunneling of electrons between a quantum well and an n+ electrode while varying the density of electrons in the well. The sample is a ‘‘tunnel capacitor’’ structure in which a GaAs well is separated by an AlGaAs tunnel barrier from the bottom n+ electrode and by a much thicker AlGaAs barrier from the top n+ electrode. In a regime where the transverse wave vector cannot be conserved in the absence of scattering, we present a model that includes scattering effects and show that it agrees with our experimental data and can be used to draw some conclusions about the efficacy of spacer layers to reduce these scattering effects.
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73.40.Gk Tunneling
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)

High acceptor production rate in electron‐irradiated n‐type GaAs: Impact on defect models

D. C. Look

Appl. Phys. Lett. 51, 843 (1987); http://dx.doi.org/10.1063/1.98831 (3 pages) | Cited 9 times

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Defect production rates have been studied in electron‐irradiated GaAs by temperature‐dependent Hall‐effect (TDH) measurements. The TDH results agree well with deep level transient spectroscopy (DLTS) results for the well‐known electron traps E1, E2, and E3, but conclusively demonstrate a much higher production rate (4±1 cm−1) of acceptors below E3 than the total of all other DLTS traps. These findings strongly affect current defect models, and, e.g., are consistent with the existence of Ga sublattice damage, not seen before.
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61.80.Fe Electron and positron radiation effects
72.20.My Galvanomagnetic and other magnetotransport effects
71.55.Eq III-V semiconductors
61.72.J- Point defects and defect clusters

Raman scattering study of alloyed Au‐Ge ohmic contacts to GaAs

D. Kirillov and Y. Chung

Appl. Phys. Lett. 51, 846 (1987); http://dx.doi.org/10.1063/1.98832 (3 pages) | Cited 11 times

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Raman scattering was applied to study alloying of the Au‐Ge‐GaAs ohmic contact structure. The Ge layer was found to be amorphous as deposited, but transformed into polycrystalline Ge after alloying. Ge diffusion into the GaAs did not result in the formation of n+‐GaAs. A broadband in the Raman spectra was found and attributed to electronic scattering by electrons in the GaAs trapped by deep levels formed by Ge and Au diffusion. These results were consistent with a model in which conduction through the contact occurred by resonant tunneling assisted by impurity levels in the graded Ge‐GaAs heterojunction structure.
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73.40.Ns Metal-nonmetal contacts
78.30.-j Infrared and Raman spectra
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Oxygen precipitation in heavily boron‐doped silicon crystals

H. L. Tsai, A. E. Stephens, and F. O. Meyer

Appl. Phys. Lett. 51, 849 (1987); http://dx.doi.org/10.1063/1.98833 (3 pages) | Cited 2 times

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Transmission electron microscopy was applied to study oxygen precipitation in P+ wafers by comparison with that in P− wafers grown in the same puller under the same growth schedule. Besides the higher precipitate density in P+ wafers for all heat treatments, it was shown that nucleation centers can be easily re‐established in P+ wafers at a low temperature after a prior denuding anneal. The precipitate morphology was found to depend on the precipitate growth rate and/or the presence of impurities. The morphology evolution from a small polyhedron to a large plate during the precipitate growth is proposed to explain the observed shapes.
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81.30.Mh Solid-phase precipitation
81.40.Gh Other heat and thermomechanical treatments
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination

Critical current densities and transport in superconducting YBa2Cu3O7−δ films made by electron beam coevaporation

B. Oh, M. Naito, S. Arnason, P. Rosenthal, R. Barton, M. R. Beasley, T. H. Geballe, R. H. Hammond, and A. Kapitulnik

Appl. Phys. Lett. 51, 852 (1987); http://dx.doi.org/10.1063/1.98834 (3 pages) | Cited 145 times

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Thin films of the high Tc superconductor YBa2Cu3O7−δ were prepared and characterized. The films made on SrTiO3 showed epitaxial growth and high critical current densities in excess of 9×104 at 78 K and 2×106 at 4.2 K. Also, surface pinning in the parallel direction was found to be very high. The measurements put a lower limit on the depairing critical current density of 5×107 A/cm2.
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74.25.Sv Critical currents
74.62.Bf Effects of material synthesis, crystal structure, and chemical composition
74.70.-b Superconducting materials other than cuprates
74.78.-w Superconducting films and low-dimensional structures
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
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