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20 Jun 1988

Volume 52, Issue 25, pp. 2099-2192

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InGaAsP multiple quantum well lasers with planar buried heterostructure prepared by metalorganic chemical vapor deposition

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

Appl. Phys. Lett. 52, 2099 (1988); http://dx.doi.org/10.1063/1.99547 (3 pages) | Cited 3 times

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Planar buried heterostructure InGaAsP multiple quantum well (MQW) lasers consisting of six InGaAsP (λg =1.34 μm at room temperature) wells and five InP barriers were prepared by low‐pressure metalorganic chemical vapor deposition. The threshold current was 35 mA, and the differential quantum efficiency was 45% at an emission wavelength of 1.3 μm. In the temperature range from −35 to 30 °C, the characteristic temperature was T0=57 K. No significant improvement in T0 was observed in these MQW lasers. However, stable single longitudinal mode operation could be obtained in a wide range of injection current without any mode changes. This effect was considered to be a result of gain narrowing of the MQW lasers.
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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.)

Bright white‐light electroluminescence in SrS:Pr,K thin films

Shosaku Tanaka, Shozo Ohshio, Junichi Nishiura, Hiroyuki Kawakami, Hideki Yoshiyama, and Hiroshi Kobayashi

Appl. Phys. Lett. 52, 2102 (1988); http://dx.doi.org/10.1063/1.99548 (3 pages) | Cited 14 times

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A bright white‐light electroluminescence (EL) is obtained in a SrS:Pr,K thin‐film EL device. The device shows a luminance level of 500 cd/m2 with 1 kHz drive (1500 cd/m2 at 5 kHz), which is five times as high as that obtained for a ZnS:Pr,F thin‐film EL device. The dominant EL excitation mechanism in the SrS:Pr,K device responsible for a higher EL efficiency is ascribed to a process wherein the ionization of the luminescent center occurs first. Subsequent recombination with an electron follows in which the Pr3+ center reaches a (4 f )2 excited state through a (4 f )(5d) excited state. Finally, luminescence due to the relaxation of the (4 f )2 electron configuration of the Pr3+ ion arises.
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78.60.Fi Electroluminescence
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
85.60.Jb Light-emitting devices
73.61.Ga II-VI semiconductors

Reflected degenerate four‐wave mixing on GaAs single quantum wells

A. Honold, L. Schultheis, J. Kuhl, and C. W. Tu

Appl. Phys. Lett. 52, 2105 (1988); http://dx.doi.org/10.1063/1.99549 (3 pages) | Cited 44 times

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Time‐resolved degenerate four‐wave mixing (DFWM) on two‐dimensional (2D) excitons in GaAs single quantum wells is studied. We observe backward coherent emission (DFWM signal) from the 2D excitons comparable in efficiency to that in forward direction. This reflection or backward DFWM configuration is extremely advantageous and useful in exploring optically thin semiconductor layers.
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Self‐phase modulation and optical limiting of a low‐power CO2 laser with a nematic liquid‐crystal film

I. C. Khoo, R. R. Michael, and G. M. Finn

Appl. Phys. Lett. 52, 2108 (1988); http://dx.doi.org/10.1063/1.99550 (3 pages) | Cited 20 times

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The extraordinarily large thermal refractive index gradient of a nematic liquid crystal is employed for transverse self‐phase modulation of a cw CO2 laser. The observed optical intensity limiting and switching are in good agreement with theoretical expectations and provide useful guidelines for infrared‐beam‐limiting applications.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.65.Pc Optical bistability, multistability, and switching, including local field effects
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Submillimeter high brightness pulsed x‐ray source

J. H. W. Lau, M. M. Kekez, G. D. Lougheed, and R. P. Gupta

Appl. Phys. Lett. 52, 2111 (1988); http://dx.doi.org/10.1063/1.99551 (3 pages) | Cited 5 times

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By inducing an electrical discharge in an annular gas plenum connected to a vacuum diode by a narrow annular slit, we demonstrate that microgram preionized plasma liners can be formed and imploded by a dc charged Blumlein pulser to efficiently convert electrical energy into soft x rays. The submillimeter x‐ray source can in principle be scaled to the high repetition rate needed for x‐ray lithography. In a proof of principle experiment, we have observed using krypton up to 0.5, 20, and 100 J of x‐ray output above 1.5 keV, 500 eV, and 150 eV photon energies, respectively.
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07.85.-m X- and γ-ray instruments
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.59.Mv High-voltage diodes
52.80.Vp Discharge in vacuum

Discharge interruption induced by an ArF laser in a C2H3Cl/CF4/CH4 mixture

Teruo Sasagawa, Akihiro Kawahara, and Minoru Obara

Appl. Phys. Lett. 52, 2114 (1988); http://dx.doi.org/10.1063/1.99552 (3 pages)

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We have successfully demonstrated discharge interruption induced by ArF laser irradiation in a discharge medium of C2H3Cl/CF4/CH4, using a hollow cathode type discharge tube. With a mixture of C2H3Cl/CF4/CH4 (1.8 Torr of CH4 with 0.7% of C2H3Cl and 10% of CF4), a discharge current of 1 mA (0.14 mA/cm2), and after laser irradiation of 27 mJ/cm2 (10 ns full width at half‐maximum), first a discharge current peak appeared and then the discharge current was decreased rapidly with a current decay time constant of 1.0 μs. A corresponding discharge current decay rate (dI/dt) of 1 kA/s was obtained. The discharge interruption condition was limited by the gas mixture and the total pressure. Moreover, dependences of dI/dt and the time constant (τ) on both laser fluence and discharge current were observed.
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52.80.Tn Other gas discharges
52.75.Kq Plasma switches (e.g., spark gaps)
52.38.-r Laser-plasma interactions
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables

Anisotropy of thermal expansion of GaAs on Si(001)

N. Lucas, H. Zabel, H. Morkoç, and H. Unlu

Appl. Phys. Lett. 52, 2117 (1988); http://dx.doi.org/10.1063/1.99553 (3 pages) | Cited 32 times

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We have measured the thermal expansion between 20 and 450 °C of epitaxially grown GaAs thin films on Si(001) as well as of the Si substrate by means of high‐resolution x‐ray scattering. Our results show that the thermal expansion of GaAs in the direction parallel to the film plane follows the thermal expansion of the silicon substrate and is therefore smaller than in bulk GaAs. Furthermore, the thermal expansion perpendicular to the film plane (parallel to the growth direction) exceeds the bulk GaAs value by the Poisson contribution as a result of the in‐plane constraint. The thermal expansion coefficients for GaAs films on Si(001) substrates in the directions parallel and perpendicular to the film plane are αT∥(GaAs) =3.46×10−6/K and αT⊥(GaAs) =8.91×10−6/K, respectively.
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65.40.De Thermal expansion; thermomechanical effects
68.60.Bs Mechanical and acoustical properties

Symmetry study of the Mn‐Si‐Al octagonal quasicrystal by convergent beam electron diffraction

N. Wang, K. K. Fung, and K. H. Kuo

Appl. Phys. Lett. 52, 2120 (1988); http://dx.doi.org/10.1063/1.99754 (2 pages) | Cited 11 times

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The addition of a few percent of Al to the Mn4Si alloy improved the perfection of the octagonal quasicrystal and made it possible for us to determine its point group symmetry as being 8/m or 8/mmm by convergent beam electron diffraction.
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61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling
61.66.Dk Alloys
61.05.J- Electron diffraction and scattering

Crystalline to amorphous transformation in Laves phase GdFe2 induced by hydrogen absorption

K. Aoki, A. Yanagitani, and T. Masumoto

Appl. Phys. Lett. 52, 2122 (1988); http://dx.doi.org/10.1063/1.99755 (2 pages) | Cited 5 times

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The hydrogen‐induced transformation from the crystalline to the amorphous state in GdFe2 has been studied by means of differential thermal analysis. GdFe2 absorbs hydrogen in the crystalline state above 420 K by an exothermic reaction. The resultant crystalline c‐GdFe2H3.8 alloy transforms to the amorphous a‐GdFe2H2.8 alloy above 470 K exothermally, which crystallizes to the stable phases α‐Fe and GdH2 above about 700 K. The driving force for the hydrogen‐induced transformation is suggested to be the difference in the enthalpy resulting from the different hydrogen occupation sites in both states of alloy.
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64.70.K- Solid-solid transitions
65.20.-w Thermal properties of liquids
65.40.gd Entropy
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients

Measurement of the pressure dependence of the direct band gap of In0.53Ga0.47As using stimulated emission

R. People, A. Jayaraman, K. W. Wecht, D. L. Sivco, and A. Y. Cho

Appl. Phys. Lett. 52, 2124 (1988); http://dx.doi.org/10.1063/1.99554 (3 pages) | Cited 7 times

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Stimulated emission, obtainable at high optical pumping levels, has been used to follow the pressure dependence of the Γ‐band gap of molecular beam epitaxial In0.53Ga0.47As on (001)InP. Hydrostatic pressure was generated using a diamond anvil cell, and all measurements were made at room temperature. The gap varies sublinearly with pressure for P≳10 kbar, having an initial slope of 12.44 meV/kbar. The deviation from a linear behavior is largely due to nonlinearities in the equation of state at higher pressures. The deformation potential (Ξd+ (1)/(3) Ξu−a) =−(7.79±0.4)eV, for the Γ‐band gap.
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71.20.Nr Semiconductor compounds
71.20.Ps Other inorganic compounds
62.20.F- Deformation and plasticity
78.45.+h Stimulated emission
81.40.Rs Electrical and magnetic properties related to treatment conditions

Semiconductor figure of merit for nonlinear directional couplers

E. M. Wright, S. W. Koch, J. E. Ehrlich, C. T. Seaton, and G. I. Stegeman

Appl. Phys. Lett. 52, 2127 (1988); http://dx.doi.org/10.1063/1.99555 (3 pages) | Cited 14 times

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We present numerical calculations of the material figure of merit for a variety of bulk semiconductors at room temperature. For efficient switching to be possible in a half‐beat‐length nonlinear directional coupler, a minimum material requirement is that the figure of merit should exceed unity.
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42.79.Gn Optical waveguides and couplers
42.65.Pc Optical bistability, multistability, and switching, including local field effects
42.82.-m Integrated optics
85.30.De Semiconductor-device characterization, design, and modeling

2 ps InGaAs photoconductors and their speed‐of‐response evaluation by optical pulse mixing at inherent nonlinearities

R. Loepfe, A. Schaelin, H. Melchior, M. Blaser, H. Jaeckel, and G. L. Bona

Appl. Phys. Lett. 52, 2130 (1988); http://dx.doi.org/10.1063/1.99556 (3 pages) | Cited 6 times

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Miniaturized In0.53Ga0.47As/InP photoconductors with nanosecond response times were integrated into broadband coplanar 50 Ω microwave structures and their response times shortened by 14 MeV Be3+‐ion implants. Using Carruther’s pulse‐mixing technique, which relies on the nonlinearities present in many photoconductors, we determined their speed of response to be of the order of 2 ps. Taking band‐to‐band recombination as the most probable cause of the slightly nonlinear behavior, we show that the response times determined from the mixing of partially overlapping optical pulses are indeed the intrinsic response times of the photoconductors.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Native oxides on etched Zn3P2 surfaces studied by x‐ray photoelectron spectroscopy

Yoshimine Kato and Shoichi Kurita

Appl. Phys. Lett. 52, 2133 (1988); http://dx.doi.org/10.1063/1.99756 (3 pages) | Cited 2 times

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The native oxides formed on air exposed, etched bulk polycrystalline Zn3P2 were investigated in the as‐etched condition, using x‐ray photoemission spectroscopy. The sputter‐etched surfaces appeared to be composed primarily of ZnO with a small concentration of P2O3 or phosphate underneath. The bromine‐methanol etched surfaces were less oxidized, and the native oxides appeared to become predominantly of phosphorus compound oxides. P2O5 was not observed in either case.
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81.65.-b Surface treatments
84.60.Jt Photoelectric conversion
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
68.35.Dv Composition, segregation; defects and impurities

Depletion charge measurements by tunneling spectroscopy GaAs‐GaAlAs field‐effect transistors

J. Smoliner, E. Gornik, and G. Weimann

Appl. Phys. Lett. 52, 2136 (1988); http://dx.doi.org/10.1063/1.99655 (3 pages) | Cited 30 times

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The subband energies on GaAs‐GaAlAs field‐effect transistor samples were measured by tunneling spectroscopy using a structure, where the tunneling process starts from an accumulation layer, and a conventional structure, where the electrons tunnel from a metal electrode into the two‐dimensional electron gas. Self‐consistent calculations were performed to determine the depletion charge from the measured subband energies. Furthermore, the influence of a backgate voltage was investigated both experimentally and theoretically. As far as we know, this is the first direct determination of the depletion charge in GaAs‐GaAlAs field‐effect transistor structures.
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85.30.Tv Field effect devices
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.40.Gk Tunneling
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Thermal donor formation and the loss of oxygen from solution in silicon heated at 450 °C

M. Claybourn and R. C. Newman

Appl. Phys. Lett. 52, 2139 (1988); http://dx.doi.org/10.1063/1.99557 (3 pages) | Cited 14 times

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A calibration is established which allows the thermal donor (TD) concentration in heat‐treated Czochralski (CZ) silicon to be determined taking account of the fact that TD centers are double donors. It is then shown that for CZ samples heated at 450 °C, 13 oxygen atoms are lost from solution during the time taken to produce one TD center. It appears that TD production is a minority process in relation to oxygen precipitation.
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61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients
71.55.Ht Other nonmetals
61.72.jd Vacancies
61.72.jj Interstitials
72.80.Cw Elemental semiconductors

Disordering of the ordered structure in metalorganic chemical vapor deposition grown Ga0.5In0.5P on (001) GaAs substrates by zinc diffusion

F. P. Dabkowski, P. Gavrilovic, K. Meehan, W. Stutius, J. E. Williams, M. A. Shahid, and S. Mahajan

Appl. Phys. Lett. 52, 2142 (1988); http://dx.doi.org/10.1063/1.99558 (3 pages) | Cited 41 times

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Transmission electron microscopy is used to study sublattice atomic ordering in as‐grown and Zn‐diffused epitaxial layers of Ga0.5In0.5P that are grown lattice matched to GaAs by low‐pressure metalorganic chemical vapor deposition. The as‐grown Ga0.5In0.5P layers exhibit an ordered trigonal structure with In‐Ga ordering occurring on only two sets of {111} planes. After a Zn diffusion is performed at 650 °C, the ordered structure is no longer observed in selected area diffraction patterns. Simultaneously, the room‐temperature photoluminescence peak shifts by ≊90 meV to higher energy, as compared to the undiffused samples. These data provide direct experimental evidence that Ga0.5In0.5P with an ordered distribution of Ga and In atoms on the column III sublattice can be converted to a random alloy by Zn diffusion.
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68.55.-a Thin film structure and morphology
66.30.J- Diffusion of impurities
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Experimental characterization of two‐dimensional dopant profiles in silicon using chemical staining

Ravi Subrahmanyan, Hisham Z. Massoud, and Richard B. Fair

Appl. Phys. Lett. 52, 2145 (1988); http://dx.doi.org/10.1063/1.99559 (3 pages) | Cited 1 time

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An experimental technique for the measurement of two‐dimensional impurity diffusion profiles in silicon has been developed. Both the lateral and in‐depth extent of dopant diffusion under a mask edge are magnified mechanically by sawing and angle lapping, and the magnified junction contour is delineated by chemical staining. The two‐dimensional shape of the junction is reconstructed from the measured stained contour. A complete diffusion profile consisting of several isoconcentration contours can be obtained by measuring the junction shape on a series of samples with increasing substrate resistivities, provided the doping level in the substrate does not affect the diffusion of the impurity under study. Results of the two‐dimensional diffusion of boron in silicon at 1050 °C are presented.
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61.72.uf Ge and Si
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients
66.30.J- Diffusion of impurities

Overshoot in the response of a photoconductor excited by subpicosecond pulses

A. Evan Iverson, G. M. Wysin, D. L. Smith, and Antonio Redondo

Appl. Phys. Lett. 52, 2148 (1988); http://dx.doi.org/10.1063/1.99560 (3 pages) | Cited 21 times

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Experiments designed to observe velocity overshoot in GaAs photoconductors excited by 2.0 eV photons are discussed. Monte Carlo transient velocity computations are presented which indicate that, for 620 nm (2.0 eV) excitation of GaAs, velocity overshoot will not occur for fields less than 20 kV/cm. Photoconductive device model equations are solved numerically for the case of subpicosecond‐pulse excitation. The computed photoconductor response is observed to have an overshoot on the picosecond time scale resulting from charge‐separation effects. The overshoot behavior is very similar to that observed in measurements of subpicosecond photoconductor response and previously interpreted in terms of velocity overshoot. We conclude that experimentally observed overshoot response at 620 nm is the result of charge‐separation effects and not the result of velocity overshoot.
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85.60.Gz Photodetectors (including infrared and CCD detectors)
72.40.+w Photoconduction and photovoltaic effects

Characteristics of p‐n junctions fabricated on Hg1−xCdxTe epilayers grown by molecular beam epitaxy

J. P. Faurie, S. Sivananthan, M. Lange, R. E. Dewames, A. M. B. Vandewyck, G. M. Williams, Dan Yamini, and E. Yao

Appl. Phys. Lett. 52, 2151 (1988); http://dx.doi.org/10.1063/1.99561 (3 pages) | Cited 6 times

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p‐n junctions have been fabricated, using the ion implantation technique, on a Hg1−xCdxTe epilayer grown by molecular beam epitaxy (MBE) on a CdTe(111)B substrate. These junctions have been made on as‐grown p‐type layers, 12 μm thick. The layer (x=0.34) exhibits at 77 K a hole mobility of 800 cm2 V−1 s−1 and a carrier concentration of 3.6×1015 cm−3. The diode dark currents in the diffusion regime and the spectral response attest to the excellent uniformity in composition of the layer. We have also established that in the diffusion regime the data can be explained by the ideal diode equation with electrical parameters measured on the as‐grown MBE layers. We consider this an important step in the understanding of the relationship between material parameters and device performance.
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73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
68.55.Nq Composition and phase identification
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
85.30.De Semiconductor-device characterization, design, and modeling

Electroabsorption of highly confined systems: Theory of the quantum‐confined Franz–Keldysh effect in semiconductor quantum wires and dots

D. A. B. Miller, D. S. Chemla, and S. Schmitt‐Rink

Appl. Phys. Lett. 52, 2154 (1988); http://dx.doi.org/10.1063/1.99562 (3 pages) | Cited 82 times

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Semiconductor quantum wells are known to show large electroabsorption (e.g., the quantum‐confined Stark effect) that results in low‐energy optical modulating and switching devices. We show theoretically that the electroabsorption and associated electrorefraction in lower dimensional structures could be much larger, suggesting very low energy devices. We illustrate the theory with specific calculations for hypothetical GaAs‐like quantum wires and dots.
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78.20.Jq Electro-optical effects
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Effects of Na2S and (NH4)2S edge passivation treatments on the dark current‐voltage characteristics of GaAs pn diodes

M. S. Carpenter, M. R. Melloch, M. S. Lundstrom, and S. P. Tobin

Appl. Phys. Lett. 52, 2157 (1988); http://dx.doi.org/10.1063/1.99563 (3 pages) | Cited 107 times

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We have investigated the dark current‐voltage characteristics of GaAs pn homojunctions whose surfaces have been passivated with Na2S and (NH4)2S chemical treatments. Reductions in 2kT perimeter recombination currents by a factor of 3.2 were obtained for the two treatments. A shunt leakage, observed at low forward bias for the Na2S treated devices, is virtually eliminated with the (NH4)2S treatment. It is also shown that even the high quality, large area (0.25 cm2) pn diodes used in this study are dominated by 2kT edge currents before passivation.
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81.40.Rs Electrical and magnetic properties related to treatment conditions
85.30.Kk Junction diodes
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.20.At Surface states, band structure, electron density of states

Structure and electrical properties of TiN/GaAs Schottky contacts

J. Ding, Z. Liliental‐Weber, E. R. Weber, J. Washburn, R. M. Fourkas, and N. W. Cheung

Appl. Phys. Lett. 52, 2160 (1988); http://dx.doi.org/10.1063/1.99564 (3 pages) | Cited 11 times

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The interface structure and morphology of TiN/GaAs contacts before and after annealing at 500, 700, and 850 °C have been investigated by transmission electron microscopy. Results reveal that pocket‐like protrusions are formed beneath the interface after annealing at 500 °C. These pockets increased in number and maximum size with increased annealing temperature. Outdiffusion of Ga and/or As along high angle grain boundaries between columnar structure of the as‐deposited TiN thin film has been proposed as being responsible for the pocket formation. The changes of electrical characteristics of these materials after annealing have been related to the formation of these pockets.
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68.35.B- Structure of clean surfaces (and surface reconstruction)
73.40.Ns Metal-nonmetal contacts
73.40.Ei Rectification
73.30.+y Surface double layers, Schottky barriers, and work functions

Three‐dimensional integration of resonant tunneling structures for signal processing and three‐state logic

Robert C. Potter, Amir A. Lakhani, Dana Beyea, Harry Hier, Erica Hempfling, and Ayub Fathimulla

Appl. Phys. Lett. 52, 2163 (1988); http://dx.doi.org/10.1063/1.99565 (2 pages) | Cited 18 times

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We have developed structures with two well‐defined negative differential resistance (NDR) regions by sequentially growing two resonant tunneling devices separated by an n+ connecting layer. Devices fabricated from these structures exhibited three stable operating points for multilevel logic circuits and were used in circuits which multiplied the input signal frequency by 3 or 5. This approach can be extended to obtain more than two NDR regions by vertical integration of additional resonant tunneling structures.
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73.40.Gk Tunneling
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
07.50.Ek Circuits and circuit components

Penetration depths of high Tc films measured by two‐coil mutual inductances

A. T. Fiory, A. F. Hebard, P. M. Mankiewich, and R. E. Howard

Appl. Phys. Lett. 52, 2165 (1988); http://dx.doi.org/10.1063/1.99757 (3 pages) | Cited 96 times

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A fundamental parameter of sample quality in epitaxial films of high Tc oxides is the effective penetration depth λ∥ of the superconducting sheet. A contactless audio‐frequency method is described, in which an epitaxial YBa2Cu3O7 film is sandwiched between sets of stacked coils, and the procedure is given for computing the complex sheet impedance and hence λ∥ from the change in mutual inductance produced by screening currents in the film. Temperature dependence of the complex impedance is presented.
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74.25.Ha Magnetic properties including vortex structures and related phenomena
74.70.-b Superconducting materials other than cuprates
74.78.-w Superconducting films and low-dimensional structures

Performance of a fully superconducting microwave cavity made of the high Tc superconductor Y1Ba2Cu3Oy

C. Zahopoulos, W. L. Kennedy, and S. Sridhar

Appl. Phys. Lett. 52, 2168 (1988); http://dx.doi.org/10.1063/1.99758 (3 pages) | Cited 22 times

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We report the successful fabrication and characterization of a high Tc superconducting microwave cavity. The cavity made of bulk Y1Ba2Cu3Oy (Tc=93 K) and dielectrically loaded with sapphire was resonant at 8.00 GHz in the TE011 mode. At 77 K the Q was 104, which represents an improvement of a factor of 11 from the normal state. At 4.2 K the Q was nearly 105. The temperature dependence of the Q correlates extremely well with the microwave surface resistance of a test sample measured independently, clearly showing that the Q was limited by the intrinsic materials preparation and not by extraneous factors.
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85.25.Qc Superconducting surface acoustic wave devices and other superconducting devices
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
84.40.-x Radiowave and microwave (including millimeter wave) technology
74.70.-b Superconducting materials other than cuprates
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