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1 Apr 1984

Volume 44, Issue 7, pp. 649-708


Error rate measurement for single photon detection at 1.3 μm

B. F. Levine and C. G. Bethea

Appl. Phys. Lett. 44, 649 (1984); http://dx.doi.org/10.1063/1.94864 (2 pages) | Cited 1 time

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We have performed single photon detection experiments at 1.3 μm and measured the error rate re. This quantity is relevant for the possible use of such a detector as a quantum limited lightwave receiver. We have also determined the dependence of re on the quantum efficiency η.
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42.79.Ls Scanners, image intensifiers, and image converters
42.79.Pw Imaging detectors and sensors
42.79.Sz Optical communication systems, multiplexers, and demultiplexers
06.20.-f Metrology

Optical stethoscopy: Image recording with resolution λ/20

D. W. Pohl, W. Denk, and M. Lanz

Appl. Phys. Lett. 44, 651 (1984); http://dx.doi.org/10.1063/1.94865 (3 pages) | Cited 792 times

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Subwave length‐resolution optical image recording is demonstrated by moving an extremely narrow aperture along a test object equipped with fine‐line structures. Details of 25‐nm size can be recognized using 488‐nm radiation. The result indicates a resolving power of at least λ/20 which is to be compared with the values of λ/2.3 obtainable in conventional optical microscopy.
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42.30.-d Imaging and optical processing
07.60.Pb Conventional optical microscopes

Strained‐layer quantum‐well injection laser

W. D. Laidig, P. J. Caldwell, Y. F. Lin, and C. K. Peng

Appl. Phys. Lett. 44, 653 (1984); http://dx.doi.org/10.1063/1.94866 (3 pages) | Cited 47 times

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Data are presented demonstrating room‐temperature operation of a strained‐layer quantum‐well injection laser. The laser structure, grown by molecular beam epitaxy, consists of an active region with three InxGa1−xAs (x∼0.35) quantum wells (LZ ∼40 Å) separated by two GaAs barriers (LB ∼30 Å). These layers are centered in a larger GaAs collection/confinement region (LZ ∼1600 Å) bounded by AlyGa1−yAs ( y∼0.45) cladding layers. The lasers operate at λ∼1.0 μm with greater than 4‐mW optical power output/facet under pulsed conditions at 300 K. Threshold current densities between 1000 and 2000 A/cm2 are obtained.
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42.55.Px Semiconductor lasers; laser diodes
78.45.+h Stimulated emission
85.30.-z Semiconductor devices
68.55.-a Thin film structure and morphology

Multiplexing the bistable boundary layer liquid crystal display

Donna Cowell Senft, Gary D. Boyd, and R. N. Thurston

Appl. Phys. Lett. 44, 655 (1984); http://dx.doi.org/10.1063/1.94867 (3 pages) | Cited 4 times

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Shorter switching times in liquid crystal devices are traditionally achieved by raising the switching voltage. However, one of the limitations in multiplexing the boundary layer display is the necessity to keep the rms switching voltage Vs on the not‐yet‐selected pels below a critical threshold voltage Vth that would hold them in an asymmetric state and prevent switching. By using a periodic square wave to simulate a sequence of bipolar switching pulses, we show that their orienting effect in a ‘‘dual‐frequency’’ liquid crystal can be prevented by simultaneously applying a voltage at a higher frequency where the dielectric anisotropy is negative. This permits Vs>Vth, and in principle allows faster multiplexing. The goal of increased speed was not achieved in our simulation experiment due to the inherently slow response of the dual‐frequency material used. Nevertheless, the demonstrated scheme will be advantageous when faster dual‐frequency materials are developed.
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85.60.Pg Display systems
78.20.Jq Electro-optical effects
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
73.30.+y Surface double layers, Schottky barriers, and work functions

Ultranarrow linewidth, magnetically switched, long pulse, xenon chloride laser

Thomas J. Pacala, I. Stuart McDermid, and James B. Laudenslager

Appl. Phys. Lett. 44, 658 (1984); http://dx.doi.org/10.1063/1.94868 (3 pages) | Cited 22 times

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A spectral linewidth of <7×10−4 A and diffraction‐limited beam divergence has been obtained from a long pulse, electric discharge xenon chloride laser with intracavity Fabry–Perot etalons. A gain duration of 100 ns provided for multipass operation of the etalons, significantly improving both contrast and finesse. The electrical discharge circuit required to produce this long gain duration was comprised of a pulse forming network, saturable inductor magnetic switch, and a tapered, constant impedance, interface transmission line.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
84.32.Dd Connectors, relays, and switches
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
42.60.By Design of specific laser systems

Extreme‐ultraviolet and x‐ray emission and amplification by nonrelativistic electron beams traversing a superlattice

A. E. Kaplan and S. Datta

Appl. Phys. Lett. 44, 661 (1984); http://dx.doi.org/10.1063/1.94869 (3 pages) | Cited 12 times

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High‐energy electrons emit resonant electromagnetic radiation when passing through a spatially periodic medium. It is conventionally assumed that ultrarelativistic electron beams are required to obtain significant emission. We demonstrate theoretically the feasibility of exploiting solid‐state superlattices with short spatial periods to obtain both spontaneous and stimulated emission in the extreme‐ultraviolet and soft x‐ray range using nonrelativistic beams.
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78.45.+h Stimulated emission
79.20.Kz Other electron-impact emission phenomena
41.75.Fr Electron and positron beams

Laser produced plasma in crystalline α‐Al2O3 and aluminum metal

Joshua E. Rothenberg and Gad Koren

Appl. Phys. Lett. 44, 664 (1984); http://dx.doi.org/10.1063/1.94870 (3 pages) | Cited 26 times

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A comparative study of the laser produced plasma (LPP) in vacuum at the surface of transparent crystalline α‐Al2O3 (sapphire) and Al metal generated by 248‐nm excimer laser pulses of 15‐ns duration is reported. It was found that the threshold fluence for strong LPP emission in sapphire is 0.55 J/cm2, which is significantly lower than that needed for the same process in clean Al (1.7 J/cm2). At fluences higher than 4 J/cm2 the LPP emission from both targets is similar. The results obtained in sapphire require that its absorption coefficient increase by many orders of magnitude during the laser pulse. A possible explanation for the observed threshold difference is that the greater thermal diffusivity of Al more than compensates for its greater volatility; hence, a greater fluence is necessary to create the LPP in Al.
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79.20.Ds Laser-beam impact phenomena
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)

Effects of the internally produced nonthermal electrons on the temperature diagnostics of a hollow gas shell Z pinch

Bruce A. Hammel and Larry A. Jones

Appl. Phys. Lett. 44, 667 (1984); http://dx.doi.org/10.1063/1.94863 (3 pages) | Cited 14 times

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Experimental evidence is presented indicating that a nonthermal electron energy distribution occurs in a collapsing gas shell Z pinch at the time of pinch. It is estimated that these results can be explained if less than 10% of the current is associated with an energetic (∼4 keV) electron beam. Interpreting the spectroscopic diagnostics consistently with the nonthermal electron energy distribution indicates that the temperature of the plasma ‘‘hot spots’’ could be as low as ∼400 eV instead of the 1 keV obtained by assuming a thermal distribution.
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52.55.Ez Theta pinch
52.70.Kz Optical (ultraviolet, visible, infrared) measurements

Structure of reactively magnetron sputtered Hf‐N films

B. O. Johansson, J.‐E. Sundgren, U. Helmersson, and M. K. Hibbs

Appl. Phys. Lett. 44, 670 (1984); http://dx.doi.org/10.1063/1.94871 (3 pages) | Cited 17 times

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In spite of the technical interest in the Hf‐N system the form of the phase diagram is not yet clear, and therefore it is difficult to predict the phase composition of thin films. In this letter Hf‐N films have been prepared by reactive dc planar magnetron sputtering and the phase composition of the films investigated by x‐ray diffraction. Between the α‐Hf and HfN single phase regions a multiphase region was found consisting of α‐Hf, ϵ‐Hf3N2, and/or ζ‐Hf4N3 and also HfN in the nitrogen rich part. For the mononitride a lattice parameter of 4.54 Å was found which is slightly higher than reported bulk vlaues. This deviation is caused by intrinsic stresses in the films. If the nitrogen content is increased above that of the mononitride, the (111) interplanar distance increases further while all other interplanar distances decrease. At still higher nitrogen contents new reflections start to appear indicating a new phase. In this region the films also change from being conducting and nontransparent to electrically insulating and transparent.
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81.15.Cd Deposition by sputtering
68.55.-a Thin film structure and morphology
61.05.C- X-ray diffraction and scattering
61.66.Fn Inorganic compounds

Structural dependence of percolation in germanium films

J. Gonzalez‐Hernandez, D. Martin, S. S. Chao, and R. Tsu

Appl. Phys. Lett. 44, 672 (1984); http://dx.doi.org/10.1063/1.94872 (3 pages) | Cited 6 times

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The critical volume fraction of percolation in conductivity has been determined for di‐phasic Ge films. Unlike Si, two values were found, 0.15 and 0.4, corresponding respectively to low and high substrate temperatures. Furthermore, scanning electron microscopy revealed a random spherical growth for the former value as contrast to an essentially columnar growth for the latter. The higher and lower values are consistent with the theoretical limits for two‐ and three‐dimensional percolation.
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71.30.+h Metal-insulator transitions and other electronic transitions
68.55.-a Thin film structure and morphology
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors

Contribution of oscillating mass transfer to the photoacoustic effect

P. Korpiun

Appl. Phys. Lett. 44, 675 (1984); http://dx.doi.org/10.1063/1.94873 (2 pages) | Cited 9 times

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In a gas‐microphone cell absorption of modulated light causes oscillating transport of heat and of mass as well. The transport of mass is described by the diffusion equation. The concentration of substance from sample or sorbate at the sample to gas boundary is obtained from the vapor pressure. Introduction of an average molar concentration variation leads to a pressure variation. Results of calculations can explain recently measured data very well. For water at 40 °C oscillating mass transfer contributes the same amount to pressure variation as the heat wave.
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78.90.+t Other topics in optical properties, condensed matter spectroscopy and other interactions of particles and radiation with condensed matter (restricted to new topics in section 78)
68.03.Fg Evaporation and condensation of liquids
66.10.-x Diffusion and ionic conduction in liquids
44.25.+f Natural convection

Organometallic vapor phase epitaxial growth of GaAs0.5Sb0.5

M. J. Cherng, G. G. Stringfellow, and R. M. Cohen

Appl. Phys. Lett. 44, 677 (1984); http://dx.doi.org/10.1063/1.94874 (3 pages) | Cited 28 times

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The pseudobinary III/V system GaAs1−ySby is well known to have a solid phase miscibility gap with a critical temperature of 751 °C. We have succeeded in growing epitaxial layers of GaAs0.5Sb0.5 lattice matched to InP at temperatures of 600 and 630 °C using the organometallic vapor phase epitaxy technique. The key requirement is a III/V ratio of greater than unity. This leads to the incorporation of all As and Sb reaching the interface and the ability to grow metastable alloys. The epitaxial GaAs0.5Sb0.5 layers have excellent surface morphology and efficient photoluminescence at a wavelength of 1.6  μm.
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68.55.-a Thin film structure and morphology
81.10.Bk Growth from vapor
64.70.-p Specific phase transitions
61.50.Nw Crystal stoichiometry

32×32 planar IR photovoltaic mosaic arrays on sputtered CdxHg1−xTe epilayers

R. Roussille, D. Amingual, R. Boch, G. L. Destefanis, and J. L. Tissot

Appl. Phys. Lett. 44, 679 (1984); http://dx.doi.org/10.1063/1.94875 (3 pages) | Cited 5 times

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Epitaxial n‐type CdxHg1−xTe layers on (111) CdTe substrates have been grown between 250 and 300 °C by sputtering deposition. The standard growth rate was nominally 2  μm/h for a thickness range from 10 to 30  μm. Typical electron concentration in CdxHg1−xTe layers with Cd composition of 0.34 is around of 2×1016 cm−3 with a Hall mobility of 20 000 cm2 V−1 s−1 at 77 K. Films can be converted to  p type after annealing. We report for the first time the characteristics of backside illuminated 32×32 planar photovoltaic mosaic arrays processed on sputtered layers. Hybrid structures have been fabricated and evaluated; the preliminary results indicate the suitability of these mosaics for hybrid focal plane applications.
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68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors
85.60.Gz Photodetectors (including infrared and CCD detectors)

Semitransparent silicide electrodes utilizing interaction between hydrogenated amorphous silicon and metals

K. Seki, H. Yamamoto, A. Sasano, and T. Tsukada

Appl. Phys. Lett. 44, 682 (1984); http://dx.doi.org/10.1063/1.94876 (2 pages) | Cited 9 times

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Thin silicide layers are found to be formed through solid state reaction between hydrogenated amorphous silicon (a‐Si:H) and metals. The method of formation of the silicide layer is very simple: deposition of metal, annealing, and etching of the residual metal layer. The reaction kinetics and properties of this layer are described. The thickness of this silicide layer is estimated to be less than 100 Å. Accordingly, it can be used as the semitransparent electrode in a‐Si:H photodiodes. This layer is more chemically stable than such conventional transparent semiconductive oxides as indium tin oxide (ITO). Photodiodes using this semitransparent electrode have as good optical and electrical characteristics as conventional a‐Si:H photodiodes using ITO.
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73.40.Ns Metal-nonmetal contacts
66.30.Ny Chemical interdiffusion; diffusion barriers
75.20.Ck Nonmetals
85.60.Dw Photodiodes; phototransistors; photoresistors

Nitridization of gallium arsenide surfaces: Effects on diode leakage currents

S. J. Pearton, E. E. Haller, and A. G. Elliot

Appl. Phys. Lett. 44, 684 (1984); http://dx.doi.org/10.1063/1.94877 (3 pages) | Cited 17 times

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Nitridization of GaAs surfaces by exposure to a nitrogen or nitrogen‐hydrogen plasma is known to form a surface coating rich in GaN. We show that pretreatment in a hydrogen plasma at room temperature followed by production of this wider band‐gap material by nitrogen plasma treatment at 500 °C for 5 h reduces the reverse leakage current of Au‐GaAs (ND−NA =5×1017 cm−3) Schottky diodes by typically an order of magnitude at 300 K.
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73.20.Hb Impurity and defect levels; energy states of adsorbed species
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
81.65.-b Surface treatments
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)

Recrystallization of silicon film on insulating layers using a laser beam split by a birefringent plate

Nao‐aki Aizaki

Appl. Phys. Lett. 44, 686 (1984); http://dx.doi.org/10.1063/1.94878 (3 pages) | Cited 13 times

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20‐μm‐wide, 1‐mm‐long, single‐crystal Si films on SiO2 have been produced using a cw Ar laser beam split by a birefringent quartz plate. The single‐scan recrystallized region width has been widened by multiple beam splitting. The resultant single‐crystal region obtained by multiple scan from the seed is a 90‐μm‐wide and 100‐μm‐long area with rare grain boundaries. This split beam method uses the stable and highly efficient TEM00 mode and needs no prepatterned antireflection layers.
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81.10.Jt Growth from solid phases (including multiphase diffusion and recrystallization)
79.20.Ds Laser-beam impact phenomena
42.79.Bh Lenses, prisms and mirrors
42.79.Fm Reflectors, beam splitters, and deflectors
68.55.-a Thin film structure and morphology

Picosecond degenerate four‐wave mixing through orientation and concentration gratings in GaAs

J. L. Oudar, I. Abram, and C. Minot

Appl. Phys. Lett. 44, 689 (1984); http://dx.doi.org/10.1063/1.94879 (3 pages) | Cited 18 times

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We report the observation of degenerate four‐wave mixing in GaAs above the band gap, using tunable picosecond pulses in the 1.53–1.61‐eV region. A very fast contribution due to orientational gratings of electron‐hole pairs is isolated with orthogonally polarized beams. This is observed for incident intensities down to 5 MW/cm2, i.e., two orders of magnitude lower than recently reported for germanium. Even at this relatively low power density, higher order effects are important, as evidenced by the power dependence of the conversion efficiency.
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42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
72.80.Ey III-V and II-VI semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
71.35.-y Excitons and related phenomena

Picosecond relaxation of hot carriers in highly photoexcited bulk GaAs and GaAs‐AlGaAs multiple quantum wells

Z. Y. Xu and C. L. Tang

Appl. Phys. Lett. 44, 692 (1984); http://dx.doi.org/10.1063/1.94880 (3 pages) | Cited 63 times

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The relaxation rate of hot carriers following picosecond photoexcitation in GaAs‐AlGaAs multiple quantum well structures is found to be significantly slower than the corresponding rate for bulk GaAs under high excitations. This is confirmed by a detailed comparison of the hot‐luminescence tails for the two cases using picosecond pulse and cw photoexcitations.
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72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.80.Ey III-V and II-VI semiconductors
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
78.55.-m Photoluminescence, properties and materials

Electron‐beam‐induced information storage in hydrogenated amorphous silicon devices

B. G. Yacobi

Appl. Phys. Lett. 44, 695 (1984); http://dx.doi.org/10.1063/1.94881 (3 pages) | Cited 2 times

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A new method of recording and storing information in hydrogenated amorphous silicon devices is demonstrated. The storage mechanism is based on the formation of electron‐beam‐induced defects that act as recombination centers. In the charge collection mode of a scanning probe instrument (e.g., a scanning electron microscope), areas that experience bombardment appear darker in comparison to the unbombarded regions of the device. This leads to a contrast formation for pattern recognition. Annealing of the device at about 200 °C ‘‘erases’’ the stored information.
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42.30.-d Imaging and optical processing
42.79.Vb Optical storage systems, optical disks
79.20.Kz Other electron-impact emission phenomena
85.60.-q Optoelectronic devices
61.43.Fs Glasses
61.43.-j Disordered solids

Reverse bias and heat treatment to improve performance of a‐Si solar cells

G. A. Swartz

Appl. Phys. Lett. 44, 697 (1984); http://dx.doi.org/10.1063/1.94882 (3 pages) | Cited 18 times

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Amorphous silicon solar cells deposited on tin oxide coated glass with an amorphous silicon carbide  p+ front contact layer were subjected to a reverse potential bias while at elevated temperatures. The bias‐anneal treatment improved measured values of open circuit voltage, fill factor, and overall efficiency. The treatment increases efficiency by as much as 18%. The improvement in cell performance appears to be related to an increase in the  μτ product and possibly an increase in the ionized dopant concentration of one or both contact layers.
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84.60.Jt Photoelectric conversion
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
73.61.Cw Elemental semiconductors
73.61.Ey III-V semiconductors
73.61.Ga II-VI semiconductors
73.61.Jc Amorphous semiconductors; glasses
73.61.Le Other inorganic semiconductors

Stripe‐geometry AlGaAs‐GaAs quantum‐well heterostructure lasers defined by impurity‐induced layer disordering

K. Meehan, J. M. Brown, N. Holonyak, R. D. Burnham, T. L. Paoli, and W. Streifer

Appl. Phys. Lett. 44, 700 (1984); http://dx.doi.org/10.1063/1.94883 (3 pages) | Cited 32 times

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Stripe‐geometry AlGaAs‐GaAs single quantum‐well heterostructure lasers are demonstrated in which the region complementary to the stripe (outside of and defining the stripe) is shifted to higher band gap, and lower refractive index, by low‐temperature (600 °C) Zn diffusion. Impurity‐induced Al‐Ga interdiffusion causes the single GaAs quantum well (x=0, Lz≊80 Å) outside of the stripe region to be mixed (‘‘absorbed,’’ x→x′) into the Alx′Ga1−x′As (x′∼0.3, Lz′≊0.18 μm) bulk‐layer waveguide of the crystal.
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42.55.Px Semiconductor lasers; laser diodes
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
66.30.J- Diffusion of impurities
85.60.Jb Light-emitting devices

Ion beam oxidation for Josephson circuit applications

S. S. Pei and R. B. van Dover

Appl. Phys. Lett. 44, 703 (1984); http://dx.doi.org/10.1063/1.94884 (3 pages) | Cited 5 times

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Niobium‐niobium oxide‐lead Josephson tunnel junctions have been fabricated using reactive ion beam oxidation. High quality junctions were obtained using a low beam voltage without cooling the sample to 77 K during oxidation. A Vm∼20 mV was achieved routinely at a beam voltage of 100 V and Vm≳30 mV at 67 V. Furthermore, excellent critical current uniformity was demonstrated using a 10‐cm Kaufman ion source with substrate motion implemented. A standard deviation in the critical current of 0.5% was obtained among three hundred and fifty 30×30 μm windowed junctions laid out over an area of 1.1×0.34 cm.
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74.50.+r Tunneling phenomena; Josephson effects
85.25.-j Superconducting devices
81.05.Bx Metals, semimetals, and alloys

dc getter sputtered amorphous GdCo films: Magnetic anisotropy and in‐depth chemical composition

M. Hong, E. M. Gyorgy, and D. D. Bacon

Appl. Phys. Lett. 44, 706 (1984); http://dx.doi.org/10.1063/1.94885 (3 pages) | Cited 7 times

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dc getter sputtering was used to deposit amorphous GdCo films. No bias voltage was applied to the substrates during the deposition. A uniform chemical composition throughout the depth of the film was observed using Rutherford backscattering spectrometry. These GdCo films show perpendicular magnetic anisotropy. Furthermore, the magnetic anisotropy can be well described by a uniaxial film whose easy axes are distributed within a range of 15° around the film plane normal.
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75.70.-i Magnetic properties of thin films, surfaces, and interfaces
68.60.-p Physical properties of thin films, nonelectronic
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.30.Gw Magnetic anisotropy
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