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1 Mar 1979

Volume 34, Issue 5, pp. 305-349


Freedericksz transition and anchoring effects in the oblique configuration of a nematic liquid crystal

T. Motooka, A. Fukuhara, and K. Suzuki

Appl. Phys. Lett. 34, 305 (1979); http://dx.doi.org/10.1063/1.90784 (2 pages) | Cited 7 times

Online Publication Date: 7 August 2008

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The following is theoretically shown: (1) The Freedericksz transition for nematic liquid crystals (NLC) can be defined in a clear‐cut way for cases where NLC is initially aligned uniformly in an arbitrary direction α0 and is weakly anchored to cell walls; (2) the critical magnetic field for the transition varies according to the anchoring stiffness. These transition phenomena will make it possible to estimate the anchoring stiffness at the wall.
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61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
64.70.M- Transitions in liquid crystals
64.70.P- Glass transitions of specific systems
68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
83.10.Ff Continuum mechanics

Electrical properties of semiconductor‐electrolyte (CdS‐NiCl2) using surface acoustic wave techniques

P. Das, R. T. Webster, and B. Davari

Appl. Phys. Lett. 34, 307 (1979); http://dx.doi.org/10.1063/1.90785 (3 pages) | Cited 5 times

Online Publication Date: 7 August 2008

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Spectroscopy of the cadmium sulphide–nickel chloride interface has been performed by measuring the acoustoelectric voltage induced by a SAW‐delay line. Observation of transitions at different radiation wavelengths is attributed to the presence of electronic levels at the interface.
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72.20.-i Conductivity phenomena in semiconductors and insulators
73.40.Mr Semiconductor-electrolyte contacts
68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces

A high‐intensity scanning ion probe with submicrometer spot size

R. L. Seliger, J. W. Ward, V. Wang, and R. L. Kubena

Appl. Phys. Lett. 34, 310 (1979); http://dx.doi.org/10.1063/1.90786 (3 pages) | Cited 82 times

Online Publication Date: 7 August 2008

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A liquid‐metal gallium‐ion source was imaged by unity‐magnification single‐gap accelerating lens with a postlens deflector to form a focused scanning probe. We report the dependence of the probe diameter and probe current on the lens acceptance half‐angle. The results range between probe diameters of 1000 and 5000 Å at currents of 0.12–3.0 nA for half‐angles of 1.2–6 mrad. The current density and brightness at the target for the 1000‐Å‐diam 57‐kV probe were 1.5 A/cm2 and 3.3×106 A/cm2 sr, respectively. Astigmatic probes were also produced with dimensions smaller than 1000 Å.
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07.78.+s Electron, positron, and ion microscopes; electron diffractometers
41.75.Ak Positive-ion beams
41.75.Cn Negative-ion beams
79.70.+q Field emission, ionization, evaporation, and desorption

Depth of melting produced by pulsed‐laser irradiation

Jagdish Narayan

Appl. Phys. Lett. 34, 312 (1979); http://dx.doi.org/10.1063/1.90787 (4 pages) | Cited 28 times

Online Publication Date: 7 August 2008

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The depth of melt front penetration induced by Q‐switched ruby‐laser irradiation has been measured by electron microscopy for laser pulses of different duration and energy density in silicon crystals diffused with phosphorous. In as‐diffused specimens (1100 °C 1‐h PH3 source) dislocation loops and phosphorous precipitates were distributed to a depth of about 1.0 μm. The precipitates and loops were dissolved to certain depths by irradiation with Q‐switched ruby‐laser pulses. Dissolving of precipitates provides evidence for melting by the laser radiation, and the depth over which precipitates are dissolved provides a measure of the melt front penetration depth.
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61.72.U- Doping and impurity implantation
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients
84.60.Jt Photoelectric conversion
79.20.Ds Laser-beam impact phenomena

Absorption processes in the XeCl laser

L. F. Champagne, L. J. Palumbo, and T. G. Finn

Appl. Phys. Lett. 34, 315 (1979); http://dx.doi.org/10.1063/1.90788 (4 pages) | Cited 11 times

Online Publication Date: 7 August 2008

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Transient absorption in Ne/Xe/HCl mixtures and various rare gas combinations are measured. The observed results are matched with a numerical model to determine the dominant absorbing species in the XeCl laser. In pure neon plasmas Ne∗2 is a dominant absorber. Addition of xenon greatly reduces this absorption through the mechanism of Penning ionization. Absorption is not changed by adding HCl to the optimum neon‐xenon concentration.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.60.By Design of specific laser systems

Tunable stimulated Raman scattering in the far infrared

C. K. N. Patel and Y. Yafet

Appl. Phys. Lett. 34, 318 (1979); http://dx.doi.org/10.1063/1.90789 (4 pages) | Cited 2 times

Online Publication Date: 7 August 2008

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We propose a tunable electronic Raman‐scattering process which yields tuning of the scattered frequency over ≳10 cm−1 in the far infrared. For a specific example of donor levels in GaAs and an incident photon frequency of ∼66.2 cm−1 (151 μm), a magnetic field of 10–30 kG yields Raman‐scattering cross sections of 10−24–10−23 cm2 sr−1. We show that a tunable Raman laser covering a frequency region from ∼30.7 to ∼16.0 cm−1 (i.e., from ∼325 to ∼625 μm) is feasible.
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42.55.Px Semiconductor lasers; laser diodes

Efficient hologram recording in LiNbO3 : Fe using optical pulses

Che‐Tsung Chen, Dae M. Kim, and D. von der Linde

Appl. Phys. Lett. 34, 321 (1979); http://dx.doi.org/10.1063/1.90790 (4 pages) | Cited 28 times

Online Publication Date: 7 August 2008

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A Q‐switched frequency‐doubled Nd : YAG laser was used to record holograms in LiNbO3 : Fe. For 1% diffraction efficiency, only 50 mJ/cm2 was needed, as compared to 500 mJ/cm2 for cw recording. Induced absorption, comparable in magnitude with the linear absorption at 647 nm, was observed during hologram recording. This indicates the existence of secondary absorption centers in LiNbO3 : Fe. Their contribution to the enhanced photorefractive effect is discussed.
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42.40.Kw Holographic interferometry; other holographic techniques
42.60.-v Laser optical systems: design and operation
07.60.-j Optical instruments and equipment

HgBr and HgI B‐state quenching rate constants

J. G. Eden and R. W. Waynant

Appl. Phys. Lett. 34, 324 (1979); http://dx.doi.org/10.1063/1.90791 (4 pages) | Cited 22 times

Online Publication Date: 7 August 2008

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The rate constants for quenching of the B states of HgBr and HgI by the rare gases and simple halogenated molecules have been measured. The experimental approach consisted of photodissociating either HgBr2 or HgI2 (in the presence of the desired quenching gas) and recording the subsequent radiative decay of the HgX (X=Br or I) excited‐state population. The large rate constant determined for two‐body destruction of HgBr (B) by Hg (1.3×10−10 cm3 sec−1) and bromine donors (Br2 : 5.5×10−10 cm3 sec−1) enhances the attractiveness of HgBr lasers pumped by dissociative excitation of HgBr2.
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31.50.Df Potential energy surfaces for excited electronic states
31.70.Hq Time-dependent phenomena: excitation and relaxation processes, and reaction rates
32.50.+d Fluorescence, phosphorescence (including quenching)

Intensity dependence of harmonic generation in 10‐μm laser‐produced plasmas

H. A. Baldis, N. H. Burnett, G. D. Enright, and M. C. Richardson

Appl. Phys. Lett. 34, 327 (1979); http://dx.doi.org/10.1063/1.90775 (3 pages) | Cited 5 times

Online Publication Date: 7 August 2008

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Integral harmonic intensities in the radiation scattered from nanosecond 10.6‐μm laser‐target interaction have been studied as a function of laser energy and target orientation. Measurements suggest a power‐law dependence of scattered harmonic intensity with increasing laser intensity, Inω0∝Inω0, up to ∼1×1014 W/cm2 incident with evidence of saturation above this level. The scattered harmonic light at 7ω0 was found to be fairly isotropic in front of the target.
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52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
42.65.Dr Stimulated Raman scattering; CARS
42.65.Es Stimulated Brillouin and Rayleigh scattering
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Spectral hole burning in GaAs junction lasers

Navin B. Patel, P. Brosson, and J. E. Ripper

Appl. Phys. Lett. 34, 330 (1979); http://dx.doi.org/10.1063/1.90776 (2 pages) | Cited 9 times

Online Publication Date: 7 August 2008

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Spectral hole burning corresponding to a gain reduction of the order of 1% has been observed in GaAs junction lasers. This observation is made possible by the use of the strong superradiant amplification of the spontaneous emission along the junction.
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42.55.Px Semiconductor lasers; laser diodes

The effect of free‐carrier absorption on the annealing of ion‐implanted silicon by pulsed lasers

A. Lietoila and J. F. Gibbons

Appl. Phys. Lett. 34, 332 (1979); http://dx.doi.org/10.1063/1.90777 (3 pages) | Cited 15 times

Online Publication Date: 7 August 2008

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The temperature rise in an ion‐implanted silicon sample illuminated by a pulsed laser (ruby or Nd : YAG) is determined by numerical solution of the heat‐diffusion equation. The temperature dependence of the thermal conductivity and the free‐carrier absorption are included in the calculations. The latter was found to have a very significant effect when the laser is operated in the Q‐switched mode. The analysis shows that annealing in this mode almost certainly involves melting of the sample surface. In the free‐oscillation mode, however, free‐carrier absorption is negligible, and this mode may therefore provide a method of melt‐free annealing.
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72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
61.72.U- Doping and impurity implantation
42.60.-v Laser optical systems: design and operation

Abrupt Ga1−xAlxAs‐GaAs quantum‐well heterostructures grown by metalorganic chemical vapor deposition

R. D. Dupuis, P. D. Dapkus, C. M. Garner, C. Y. Su, and W. E. Spicer

Appl. Phys. Lett. 34, 335 (1979); http://dx.doi.org/10.1063/1.90778 (3 pages) | Cited 18 times

Online Publication Date: 7 August 2008

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Multiple‐quantum‐well Ga1−xAlxAs‐GaAs heterostructures grown by metalorganic chemical vapor deposition have been analyzed by Auger electron spectroscopy combined with simultaneous argon‐ion sputter etching. The chemical‐interface widths of the Ga0.45Al0.55As‐GaAs heterojunctions are determined to be ≲17 Å. In addition, no Al is detected in the GaAs quantum wells.
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics

Passivation of grain boundaries in polycrystalline silicon

C. H. Seager and D. S. Ginley

Appl. Phys. Lett. 34, 337 (1979); http://dx.doi.org/10.1063/1.90779 (4 pages) | Cited 124 times

Online Publication Date: 7 August 2008

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Preferential diffusion of various gases down the grain boundaries in polycrystalline silicon is shown to promote significant changes in the density of defect states in these regions. A plasma of monatomic hydrogen provides a significant reduction in both the state density and the accompanying grain‐boundary potential barrier while plasmas of oxygen, nitrogen, and sulfur hexafluoride are shown to increase this density of states. Boundaries passivated with hydrogen have as much as a factor of 1000 larger transconductance after treatment. Hydrogenated barriers are stable over long periods at 375 °C and essentially indefinitely at 23 °C. The results have important implications for the development of low‐cost thin‐film silicon photovoltaic devices.
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78.30.Er Solid metals and alloys
78.40.Kc Metals, semimetals, and alloys
61.50.-f Structure of bulk crystals
61.72.-y Defects and impurities in crystals; microstructure

Transverse magnetoresistance of highly doped n‐type InSb in strong magnetic fields

Chhi‐Chong Wu and Anna Chen

Appl. Phys. Lett. 34, 340 (1979); http://dx.doi.org/10.1063/1.90780 (3 pages) | Cited 2 times

Online Publication Date: 7 August 2008

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Quantum effects are being studied in the transverse magnetoresistance of degenerate semiconductors such as highly doped n‐type InSb for the case where acoustic phonons are the dominant scattering mechanism. The result shows that the transverse magnetoresistance oscillates with the dc magnetic field owing to the degeneracy of the electron gas. However, the transverse magnetoresistance for nonparabolic bands is enhanced due to the strong magnetic field dependence.
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71.20.-b Electron density of states and band structure of crystalline solids
72.10.Di Scattering by phonons, magnons, and other nonlocalized excitations
72.20.Ht High-field and nonlinear effects
71.20.Nr Semiconductor compounds
71.20.Ps Other inorganic compounds

Nonlinear sputtering effects in thin metal films

D. A. Thompson and S. S. Johar

Appl. Phys. Lett. 34, 342 (1979); http://dx.doi.org/10.1063/1.90781 (4 pages) | Cited 52 times

Online Publication Date: 7 August 2008

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The sputtering yields of Ag, Au, and Pt have been measured for monatomic and polyatomic ions of P, As, Sb, and Bi over the energy range 15–135 keV. Very lare enhancements of the sputtering yields over those predicted by linear cascade theory have been observed. These enhancements appear to be consistent with a strong contribution resulting from the near‐surface region of the impact area and that the complete collision cascade, even for high energy densities, plays a lesser and possibly minor role. It is also shown that the enhancements can in no way be explained based upon a thermal model in which the localized high‐temperature zone is responsible for an evaporation component.
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79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
61.80.Jh Ion radiation effects

Quasiparticle heterodyne mixing in SIS tunnel junctions

P. L. Richards, T. M. Shen, R. E. Harris, and F. L. Lloyd

Appl. Phys. Lett. 34, 345 (1979); http://dx.doi.org/10.1063/1.90782 (3 pages) | Cited 41 times

Online Publication Date: 7 August 2008

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The rapid onset of quasiparitcle tunneling current in superconductor‐insulator‐superconductor (Josephson) junctions at voltages above 2Δ/e is being used for millimeter‐wave heterodyne mixing. Junctions with a 2‐μm diameter and RN=50 Ω have little capacitive shunting at the signal frequency of 36 GHz. Because there is no series resistance, residual capacitance can be tuned out. Double sideband conversion efficiencies of 0.32 and mixer noise temperatures as low as TM⩽7 K=4hν/k have been observed. The results are compared with shot‐noise‐limited mixer theory. Photon‐assisted tunneling effects are seen which indicate the approach to photon‐noise‐limited operation.
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07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
74.50.+r Tunneling phenomena; Josephson effects

Low‐noise 115‐GHz mixing in superconducting oxide‐barrier tunnel junctions

G. J. Dolan, T. G. Phillips, and D. P. Woody

Appl. Phys. Lett. 34, 347 (1979); http://dx.doi.org/10.1063/1.90783 (3 pages) | Cited 40 times

Online Publication Date: 7 August 2008

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Small‐area (≲1 μm2) oxide‐barrier tunnel junctions have been made of thermally cyclable superconducting Pb alloys for use as high‐frequency mixers. A single‐sideband mixer noise temperature of <100 K has been achieved at 115 GHz. This result was achieved in the quasiparticle (classical) mixing mode.
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74.50.+r Tunneling phenomena; Josephson effects
95.55.-n Astronomical and space-research instrumentation
85.25.-j Superconducting devices
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