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15 Feb 1972

Volume 20, Issue 4, pp. 147-179

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Comment on ``Required Monochromaticity of an Electron Beam Modulated at Optical Frequencies''

Loren Pfeiffer, D. L. Rousseau, and A. R. Hutson

Appl. Phys. Lett. 20, 147 (1972); http://dx.doi.org/10.1063/1.1654083 (2 pages) | Cited 6 times

Online Publication Date: 22 October 2003

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Recently revealed values for the energy monochromaticity and exit aperture in the Schwarz‐Hora experiment are found to be inconsistent with the claimed beam current by orders of magnitude using the Langmuir brightness relation. Accordingly, attempts to duplicate the reported experimental conditions appear futile, and claims for the effect based upon the quoted experimental conditions may be regarded with skepticism.

Energy‐Spread Structure of Electron Beams to be ``Optically'' Modulated

Helmut Schwarz

Appl. Phys. Lett. 20, 148 (1972); http://dx.doi.org/10.1063/1.1654084 (2 pages) | Cited 8 times

Online Publication Date: 22 October 2003

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Electron beams of relatively high currents (0.5 μA) and 50‐keV energy with observable modulability at optical frequencies can be produced without violating the Langmuir brightness relationship by shaping the beam in a ``filamentary'' structure, whereby each single‐beam ``filament'' fulfills the recently reported monochromaticity requirement (energy spread better than 10 meV). The monochromator and the electron‐optical‐beam ``shaper'' have to be made adjustable for accurate spatial coherence between the electron‐beam ``filaments''.

Time Dependence of Charge Transport in MIS Memory Transistors

A. V. Ferris‐Prabhu

Appl. Phys. Lett. 20, 149 (1972); http://dx.doi.org/10.1063/1.1654085 (2 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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Based on the direct tunneling model, the complete solution is obtained for the charge‐transport equation for MIS memory transistors. It is shown that the time dependence is linear in the microsecond range, roughly logarithmic in the millisecond range, and eventually saturates to a value determined by the physical characteristics of the device. For an oxide layer 20 Å thick, the theory predicts a switching time of about 45 μsec and saturation in about 150 sec.

Liquid‐Crystal Holography of High‐Frequency Acoustic Waves

Michael J. Intlekofer and David C. Auth

Appl. Phys. Lett. 20, 151 (1972); http://dx.doi.org/10.1063/1.1654086 (2 pages) | Cited 2 times

Online Publication Date: 22 October 2003

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A cholesteric liquid‐crystal area detector has been used to make acoustical holograms at 5 MHz in water. The holograms were photographed by integrated time exposure and the original images reconstructed using laser light.

Superconducting Maser: A Critical Re‐examination

A. A. Fife and Suso Gygax

Appl. Phys. Lett. 20, 152 (1972); http://dx.doi.org/10.1063/1.1654087 (3 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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The condition that the threshold current has to be less than the critical current in a superconducting injection maser is shown to be insufficient. Irrespective of the material, the number of states above the gap edge is too small to accommodate the overpopulation required to exceed all the losses in a superconductor.

Resistivity Ratio of Niobium Superconducting Cavities

E. L. Garwin and Mario Rabinowitz

Appl. Phys. Lett. 20, 154 (1972); http://dx.doi.org/10.1063/1.1654088 (3 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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Resistivity measurements have been made on Nb cavities, as well as on Pb and Cu, at 296, 77, and 4.2 °K by means of a contactless induced‐current method. For superconductors, a constant magnetic field drives the material normal below the transition temperature. These measurements provide a simple means for initial material evaluation as well as a direct means of monitoring the effects of material parameters (purity, heat treatment, gas incorporation, etc.) on the electron mean free path. Approximate determinations of Hc, Hc1, and Hc2 can also be derived from these measurements. Normal‐state thermal conductivity and the Ginzburg‐Landau parameter κ are calculated from the resistivity measurements.

Acoustic‐Wave Detection via a Piezoelectric Field‐Effect Transducer

E. W. Greeneich and R. S. Muller

Appl. Phys. Lett. 20, 156 (1972); http://dx.doi.org/10.1063/1.1654089 (3 pages) | Cited 7 times

Online Publication Date: 22 October 2003

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An oriented piezoelectric film has been incorporated in the insulator region of a silicon insulated‐gate field‐effect transistor to provide a sensitive high‐frequency strain transducer. With this device, strains as low as 10−8 have been detected and gauge factors of roughly 7000 have been attained for applied ac strains at 5.6 MHz.

Use of an Electron Flood Gun to Reduce Surface Charging in X‐Ray Photoelectron Spectroscopy

D. A. Huchital and R. T. McKeon

Appl. Phys. Lett. 20, 158 (1972); http://dx.doi.org/10.1063/1.1654090 (2 pages) | Cited 22 times

Online Publication Date: 22 October 2003

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A flood‐gun arrangement is shown to be useful in alleviating the sample‐charging problem in x‐ray photoelectron spectroscopy. Modest currents (<10−8 A) of low‐energy electrons result in the shifting of photoelectron energy peaks to the proper positions and the reduction of the peak widths.

Dye Amplifiers Pumped by One‐ and Two‐Photon Processes

John G. Kepros and Edward M. Eyring

Appl. Phys. Lett. 20, 160 (1972); http://dx.doi.org/10.1063/1.1654091 (3 pages) | Cited 2 times

Online Publication Date: 22 October 2003

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One‐ and two‐photon absorption (at 5300 Å) thresholds for laser action in aqueous bromocresol green and aqueous bromocresol purple were measured, and a novel method of measuring gain, requiring only one photomultiplier, is reported.

Minority‐Carrier Sweepout in 0.09‐eV HgCdTe

S. P. Emmons and K. L. Ashley

Appl. Phys. Lett. 20, 162 (1972); http://dx.doi.org/10.1063/1.1654092 (2 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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High‐field measurements of decreased response time, gain saturation, and enhanced signal‐to‐noise ratio are reported as evidence of minority‐carrier sweepout in 0.09‐eV HgCdTe photoconductors.

Continuous‐Chemical‐Laser Cavity Studies

D. J. Spencer, D. A. Durran, and H. A. Bixler

Appl. Phys. Lett. 20, 164 (1972); http://dx.doi.org/10.1063/1.1654093 (4 pages) | Cited 3 times

Online Publication Date: 22 October 2003

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The extent of the lasing medium along the jet axis in a continuous chemical laser is variable under changes in the jet temperature, pressure, velocity, reactant concentration, etc. The laser cavity must be readily tunable to accommodate the changes in lasing length in order to maintain maximum multimode laser power operation in a high‐Fresnel‐number cavity under variation in the jet parameters. In addition, as an aid in understanding laser performance, it is desirable to have the means to determine the multimode laser intensity distribution in the lasing region for various conditions in the jet. Techniques are presented to determine the optimum optic axis position for maximum multimode power operation, and to measure the intensity distribution along the jet and extent of the lasing medium. A flat and spherical mirror tuned during laser operation determine peak laser power position and the lasing length of the jet (typically 1. 6 in. in N2 flows). Axial local power surveys are made with this same cavity array coupled with a movable aperture which limits lasing to a small fraction of the total lasing region. A visual display of lasing length and the power distribution pattern along the jet, both axial and off‐axis, is obtained by coupling power out of one of a pair of optical flats into a lucite block.

Addition‐Elimination HF Chemical Laser

Thomas D. Padrick and George C. Pimentel

Appl. Phys. Lett. 20, 167 (1972); http://dx.doi.org/10.1063/1.1654094 (2 pages) | Cited 4 times

Online Publication Date: 22 October 2003

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Hydrogen fluoride laser emission has been observed following flash photolysis of ethylene and tetrafluorohydrazine at elevated temperatures in a Vycor laser tube. The observed emission includes only v=1→0 transitions; we believe this emission is caused by HF elimination from a chemically activated molecule formed by addition to the ethylene double bond.

Scattering‐Mode Ferroelectric‐Photoconductor Image Storage and Display Devices

W. D. Smith and C. E. Land

Appl. Phys. Lett. 20, 169 (1972); http://dx.doi.org/10.1063/1.1654095 (3 pages) | Cited 51 times

Online Publication Date: 22 October 2003

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A new type of image storage and display device is described in which the image is stored by means of a longitudinal electro‐optic scattering effect in ferroelectric ceramics. The stored image can be viewed directly or projected onto a viewing screen by using transmitted or reflected, polarized or unpolarized, white or monochromatic light. The device has the capability of selective erasure of part or all of the stored image.

Precipitation of Si from the Al Metallization of Integrated Circuits

J. O. McCaldin and H. Sankur

Appl. Phys. Lett. 20, 171 (1972); http://dx.doi.org/10.1063/1.1654096 (2 pages) | Cited 28 times

Online Publication Date: 22 October 2003

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The Al metallization of integrated circuits is known to dissolve ☒% or more Si, but the ultimate location of this Si has been uncertain. An electron microprobe operated at low beam energy so as to penetrate only the upper portion of the metallization was used to follow the movement of dissolved Si on cooling after the ``forming'' heat treatment. Dissolved Si substantially less than a diffusion length from the substrate was found to regrow there; elsewhere the Si forms precipitates in the Al matrix, preferentially near the free surface of the Al.

Coating, Mechanical Constraints, and Pressure Effects on Electromigration

N. G. Ainslie, F. M. d'Heurle, and O. C. Wells

Appl. Phys. Lett. 20, 173 (1972); http://dx.doi.org/10.1063/1.1654097 (2 pages) | Cited 30 times

Online Publication Date: 22 October 2003

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The effect of the mechanical constraints exerted by coatings upon electromigration in thin films is evaluated on the basis of known pressure effects upon diffusion.

Lasing Transitions in p+‐n‐n+ (AlGa) As☒Ga As Heterojunction Lasers

H. Kressel and H. F. Lockwood

Appl. Phys. Lett. 20, 175 (1972); http://dx.doi.org/10.1063/1.1654098 (3 pages) | Cited 14 times

Online Publication Date: 22 October 2003

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A study of the lasing and spontaneous emission from p+‐n‐n+ heterojunction lasers with lightly doped n‐type active regions shows that the stimulated emission is not due to a simple band‐to‐band recombination process. It is further shown that the 300 K gain coefficient dependence on the junction current differs greatly from that predicted on the basis of band‐to‐band lasing involving a parabolic density‐of‐states distribution.

Defining the ``Random'' Spectrum as Used in the Channeling Technique of Nuclear Backscattering

J. F. Ziegler and B. L. Crowder

Appl. Phys. Lett. 20, 178 (1972); http://dx.doi.org/10.1063/1.1654099 (2 pages) | Cited 11 times

Online Publication Date: 22 October 2003

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See Also: Erratum

Show Abstract
A new method is described for operationally defining a ``random'' spectrum as used in channeling studies of nuclear backscattering. The method is reproducible to 1%. A detailed analysis is made for the case of He4 ions backscattered from silicon crystals. Corrections are determined so the ``random'' spectrum approximates that from an amorphous layer to within ± 1%.
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