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1 Dec 1972

Volume 21, Issue 11, pp. 523-562


Emission spectra of Cd1−xMgxTe light‐emitting diodes

Takao Shitaya, Toru Ishida, and Hisanao Sato

Appl. Phys. Lett. 21, 523 (1972); http://dx.doi.org/10.1063/1.1654242 (2 pages) | Cited 1 time

Online Publication Date: 16 October 2003

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Visible light‐emitting diodes have been fabricated from Cd1−xMgxTe (x ≈ 0.43). An external quantum efficiency of 2×10−4 has been obtained at room temperature. Emission spectra of the diodes consist of two broad bands peaking at 640 and 700 mμ, relative intensities of which depend on the concentration of Al doped as donors. The photoluminescence measurements indicate that the 640‐mμ band is produced by a combination of doping P as an acceptor and heating in Cd vapor. The 700‐mμ band is enhanced by Al and is attributable to lattice defects induced by Al doping.

Segmented surface‐wave amplifier exhibiting net terminal gain at 86 MHz

G. Cambon, C. Roustan, and M. Rouzeyre

Appl. Phys. Lett. 21, 525 (1972); http://dx.doi.org/10.1063/1.1654243 (3 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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In our work on the amplification of Bleustein‐Gulyaev waves in photoconducting CdS crystals, we have found that the gain as a function of electric field is quite symmetric about the synchronous value. We have therefore been able to achieve amplification with a segmented structure consisting of an interdigital electrode. The unequal spacing between fingers produces amplification in the region where the field is positive, which is in excess of the attenuation in the region where the field is negative. The spacings between adjacent electrodes are 500 and 250 μm, giving a periodicity of 850 μm; the length of the active region is 6 mm. The experimental electronic gains obtained were 19 dB at 43 MHz and 32 dB at 86 MHz with an applied voltage of 130 V; 4 dB net gain was obtained at 86 MHz. It has been observed that the electronic gain is sensitive to the photoexciting light wavelength. We give an interpretation of this phenomenon based on the relative penetration depth of the mechanical wave, of the photoexcited carriers, and of drifting electric field.

Nonlinear interaction of Bleustein‐Gulyaev waves in photoconducting CdS

G. Sagnes, C. Roustan, and M. Rouzeyre

Appl. Phys. Lett. 21, 527 (1972); http://dx.doi.org/10.1063/1.1654244 (4 pages) | Cited 3 times

Online Publication Date: 16 October 2003

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We report on an experimental study of the nonlinear interaction of Bleustein‐Gulyaev surface waves in photoconducting CdS. The two oppositely travelling surface waves at frequency f=43 MHz are first amplified and then interact under a semitransparent diffused electrode. The acoustic convolution product is observed at 86 MHz. The level of the detected signal is 36 dB below the two input ones with an interacting length of only 2 mm. There is clear evidence that this nonlinear interaction results from electron phonon scattering; we give the expression for the second‐order potential.

Cathodoluminescence of rare‐earth oxysulfide thin films

R.V. Alves, R.A. Buchanan, and T.G. Maple

Appl. Phys. Lett. 21, 530 (1972); http://dx.doi.org/10.1063/1.1654245 (3 pages) | Cited 3 times

Online Publication Date: 16 October 2003

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Rare‐earth oxysulfide films with an intrinsic cathodoluminescent efficiency equivalent to that of the same material in powder form have been produced. These films withstood the maximum power density of the electron beam apparatus, 7 W∕mm2, without damage or intensity saturation. An apparatus‐limited luminance of 4×104 fL from a terbium‐activated lanthanum oxysulfide film using 12‐kV cathode‐ray excitation was measured. A multilayer film of lanthanum oxysulfide activated with Eu, Tb, and Tm was produced whose emission color is voltage dependent.

Stress‐pulse propagation in solids: a closer look at dispersion

M.P. Felix and A.T. Ellis

Appl. Phys. Lett. 21, 532 (1972); http://dx.doi.org/10.1063/1.1654246 (3 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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It is found that when a short‐duration plane‐compressive stress pulse is propagated in various solid metals, the initially compressive pulse develops a tensile tail indicative of dispersion. This dispersion occurs without the stress pulse impinging upon external boundaries or upon any classically recognized internal boundaries. This phenomenon also occurs in water in which it is demonstrated experimentally that the dispersion mechanism is the scattering of the wave by the small amount of air normally present in water. It is believed that the pulse dispersion in the metals is likewise caused by scattering of the wave by the very small but extremely numerous defect‐related voids that exist in all metals, even if they are carefully prepared metallic single crystals.

Guided‐wave propagation at 10.6 μm in silver bromide thin films

J.H. McFee, J.D. McGee, T.Y. Chang, and V.T. Nguyen

Appl. Phys. Lett. 21, 534 (1972); http://dx.doi.org/10.1063/1.1654247 (3 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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A germanium prism coupler has been used to couple a CO2 laser beam into thin AgBr films deposited on NaCl substrates. Thermographic phosphor screens and an infrared scanner were used to detect guided‐wave propagation in the films. Measurement of the TE0 and TM0 coupling angles yielded the film index (2.14) and thicknesses. The latter were in excellent agreement with independent thickness measurements.

Carbon monoxide chemical laser from the reaction O + Cse → CO† + Se

Curt Wittig and Ian W.M. Smith

Appl. Phys. Lett. 21, 536 (1972); http://dx.doi.org/10.1063/1.1654248 (3 pages) | Cited 3 times

Online Publication Date: 16 October 2003

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Laser emission from vibrationally excited CO (CO†) has been observed when mixtures of CSe2, O2, and He are partially dissociated by a pulsed electric discharge. Observations on the spontaneous emission confirm that the CO† is formed in the reaction O + CSe → CO†+Se, which is 118 kcal∕mole exothermic and produces CO selectively in high vibrational levels. A comparison is made with the analogous system O + CS → CO†+S.

Stimulated Brillouin scattering in optical fibers

E.P. Ippen and R.H. Stolen

Appl. Phys. Lett. 21, 539 (1972); http://dx.doi.org/10.1063/1.1654249 (3 pages) | Cited 118 times

Online Publication Date: 16 October 2003

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Observations of backward stimulated Brillouin scattering (SBS) in glass optical fibers are reported. Threshold for SBS has been achieved with less than 1 W of input power at 5355 Å. Relaxation behavior in the SBS signal has also been observed and is attributed to finite‐cell‐length oscillation. Experimental results are compared with theory, and the implied limitation to optical fiber transmission is discussed.

Observation of coherent microwave radiation emitted by coupled Josephson junctions

T.F. Finnegan and S. Wahlsten

Appl. Phys. Lett. 21, 541 (1972); http://dx.doi.org/10.1063/1.1654250 (4 pages) | Cited 46 times

Online Publication Date: 16 October 2003

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We report here the results of a preliminary study of coherent microwave radiation emitted by a small array of interacting Josephson tunnel junctions, including the first direct observation of the superradiant state in pairs of junctions.

The on‐state in chalcogenide threshold switches

S.H. Lee

Appl. Phys. Lett. 21, 544 (1972); http://dx.doi.org/10.1063/1.1654251 (3 pages) | Cited 8 times

Online Publication Date: 16 October 2003

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The on‐state of the chalcogenide glass threshold switch is analyzed on experimental results which call for thin free‐carrier space‐charge regions at the electrodes. Carriers are assumed to tunnel through the corresponding barriers which are, in turn, maintained by the joint action of the electron and hole flow. The calculated voltage‐current relationship is in excellent agreement with observations.

Charging of polymer foils using liquid contacts

P.W. Chudleigh

Appl. Phys. Lett. 21, 547 (1972); http://dx.doi.org/10.1063/1.1654252 (2 pages) | Cited 17 times

Online Publication Date: 16 October 2003

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A very simple technique is reported for charging 25.4‐ and 50.8‐μm foils of polyfluoroethylenepropylene (FEP) using conducting liquid contacts. At 23°C in laboratory atmosphere, decay time constants exceed 20 years for foils initially charged to 500 V with ethyl alcohol contacts. Measurements of accelerated decay at 100°C are interpreted in terms of rapid injection and trapping of surface charge followed by drift of thermally generated carriers under the internal field of the trapped surface charge.

High‐speed photography of surface flashover of solid insulators under impulse voltages in vacuum

J.D. Cross and K.D. Srivastava

Appl. Phys. Lett. 21, 549 (1972); http://dx.doi.org/10.1063/1.1654253 (3 pages) | Cited 12 times

Online Publication Date: 16 October 2003

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Results are presented of an investigation into the flashover of glass and high‐density alumina cylinders 1.25 cm in length between uniform field electrodes in vacuum. Photographs taken with an image‐converter camera with a framing rate of 2×107 frames∕sec are shown. At approximately 80% of the voltage required to produce a flashover, partial discharges occur. When the voltage applied to the gap is increased to breakdown level, the partial discharges persist as the first stage of a two‐stage arc formation. The development of the discharge is shown to be consistent with a flashover mechanism involving charging of the solid surface by electrons emitted at the cathode.

Observation of superconductivity in an indium‐silicon bistable device

Ronald F. Broom

Appl. Phys. Lett. 21, 551 (1972); http://dx.doi.org/10.1063/1.1654254 (3 pages) | Cited 3 times

Online Publication Date: 16 October 2003

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Superconducting behavior characteristic of a weak link is found to occur in the low‐resistance state of a bistable nonvolatile switching device, formed by two closely spaced In contacts on Si.

Phase‐matched submillimeter wave generation by difference‐frequency mixing in ZnGeP2

G.D. Boyd, T.J. Bridges, C.K.N. Patel, and E. Buehler

Appl. Phys. Lett. 21, 553 (1972); http://dx.doi.org/10.1063/1.1654255 (3 pages) | Cited 43 times

Online Publication Date: 16 October 2003

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Using two step‐tunable CO2 lasers, we have observed phase‐matched generation of frequencies 70 <ν<110 cm−1 by nonlinear mixing in a birefringent ternary semiconductor, ZnGeP2. An observed power of ∼1.7 μW at 83.37 cm−1 gave a signal‐to‐noise ratio of ∼1000 with a Ge:Ga detector. In combination with tunable optical lasers, this technique should yield a tunable source of submillimeter wave radiation for high‐resolution spectroscopy.

Vibration‐vibration energy transfer in CO2 glow discharges

M.C. Gower and A.I. Carswell

Appl. Phys. Lett. 21, 556 (1972); http://dx.doi.org/10.1063/1.1654256 (3 pages) | Cited 2 times

Online Publication Date: 16 October 2003

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Short‐duration 10.6‐μm pulses are used to perturb low‐pressure CO2 laser discharges. Various spontaneous emissions from the glow discharge are monitored as they return to their steady‐state values. Vibration‐vibration (VV) pumping between CO2(ν3) and CO (produced by dissociation or premixed) as well as N2 has been observed in three independent studies. Data obtained from these studies correlate well with each other. When the reciprocal time constant for the VV process is plotted against pressure, a straight line is obtained as predicted by theory. The slope of this line is consistent with rate‐constant data taken from laser‐induced fluorescence experiments.

Observation of the transparency of a resonant medium to zero‐degree optical pulses

H.P. Grieneisen, J. Goldhar, N.A. Kurnit, A. Javan, and H.R. Schlossberg

Appl. Phys. Lett. 21, 559 (1972); http://dx.doi.org/10.1063/1.1654257 (4 pages) | Cited 26 times

Online Publication Date: 16 October 2003

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Experiments are described in which low‐intensity laser pulses of zero area [ ∫ −∞∞E(z,t) dt = 0] are propagated through a degenerate resonantly absorbing medium with greatly reduced absorption. These pulses are constructed either electro‐optically or by allowing a non‐zero‐degree pulse to evolve toward zero area by means of a resonant absorption and reradiation process. We observe the transmission of as much as 65% of the energy of such pulses through a resonant absorber which attenuates the same cw laser by e−αL, with αL ≈ 20.
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