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1 Oct 1981

Volume 39, Issue 7, pp. 519-576


Signal enhancement in photothermal imaging produced by three‐dimensional heat flow

J. C. Murphy and L. C. Aamodt

Appl. Phys. Lett. 39, 519 (1981); http://dx.doi.org/10.1063/1.92800 (3 pages) | Cited 12 times

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Three‐dimensional thermal diffusion effects are shown to be important for photothermal imaging. Signal enhancement near thermal boundaries is observed. The effects are applied to locating defects in a crystalline ceramic. A general application to signal enhancement in powders over bulk solids is suggested.
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66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves

Magnitude of the intrinsic resonant frequency in a semiconductor laser

Thomas L. Paoli

Appl. Phys. Lett. 39, 522 (1981); http://dx.doi.org/10.1063/1.92801 (3 pages) | Cited 6 times

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The magnitude of the intrinsic resonant frequency exhibited by a semiconductor laser operating at a fixed level above threshold is shown to be determined by the product of the photon lifetime for the unpumped laser cavity and the differential lifetime of the carriers at threshold. This conclusion differs from the generally accepted view that the relevant lifetimes for the resonant frequency are the carrier and photon lifetimes evaluated at threshold and resolves the existing discrepancy between measured and calculated values. The present analysis is used to evaluate the shift in the resonant frequency produced in a typical proton‐bombarded stripe‐geometry laser by variations in the laser’s cavity loss.
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42.55.Ah General laser theory
42.55.Px Semiconductor lasers; laser diodes

Subpicosecond pulses from passively mode‐locked GaAs buried optical guide semiconductor lasers

J. P. van der Ziel, W. T. Tsang, R. A. Logan, R. M. Mikulyak, and W. M. Augustyniak

Appl. Phys. Lett. 39, 525 (1981); http://dx.doi.org/10.1063/1.92802 (3 pages) | Cited 43 times

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We report the observation of bursts of transform‐limited 0.65‐psec pulses at 1‐GHz repetition rates by passive mode locking of a buried optical guide laser in an external cavity. The lasers contain a saturable absorber at the exit facet, specifically introduced by 600‐keV proton bombardment at a 3×1015‐ cm−2 dosage level.
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42.55.Px Semiconductor lasers; laser diodes
42.79.Sz Optical communication systems, multiplexers, and demultiplexers
42.60.Fc Modulation, tuning, and mode locking

Optical gain obtained by rapidly mixing cold CO2 and hot N2 gases within a gas throat

K. Kitagawa

Appl. Phys. Lett. 39, 527 (1981); http://dx.doi.org/10.1063/1.92803 (3 pages)

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A population inversion of the (001)–(100) transition in CO2 gas has been observed when the cold CO2 or CO2, and He gases were vertically injected into a high‐temperature, thermally equilibrated, low‐subsonic N2 flow in a duct having a constant area. Simultaneously, the formation of a gas throat was observed. A small signal gain of 0.95/m was measured at 2 mm downstream from a gas injecting point.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
47.40.Hg Transonic flows
34.50.Ez Rotational and vibrational energy transfer

Phase noise of single‐mode diode lasers in interferometer systems

A. Dandridge and A. B. Tveten

Appl. Phys. Lett. 39, 530 (1981); http://dx.doi.org/10.1063/1.92804 (3 pages) | Cited 19 times

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Measurements have been made of the phase noise of six different types of single‐mode diode laser in an unbalanced Michelson interferometer, as a function of optical path difference. The frequency dependence of the phase noise has also been determined. Possible origins of the frequency fluctuations which result in the phase noise are discussed. The detrimental effect of the phase noise on the sensitivity and dynamic range of optical fiber interferometer sensors is briefly discussed.
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07.60.Ly Interferometers
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Microscopically textured optical storage media

H. G. Craighead and R. E. Howard

Appl. Phys. Lett. 39, 532 (1981); http://dx.doi.org/10.1063/1.92805 (3 pages) | Cited 12 times

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A new optical information storage technique is described which operates by irreversibly altering the absorption properties of a microscopically textured surface. Reflectance changes of greater than a factor of 100 have been obtained by local melting of the surface. A random array of Si columns with cross‐sectional dimensions less than 100 nm, formed on a Si film by reactive ion etching, has a visible reflectance of less than 0.01. By irradiation with a focused laser beam, at a power density of ≲8 mW/μm2, the columns melt to form a surface with a specular reflectance of ∼0.4. The applicability of this surface structure as a permanent optical storage medium is discussed. In general, this surface texturing can be applied to a wide variety of materials with the advantages of increased sensitivity to the writing beam, large contrast between the written and unwritten areas and reduced lateral energy flow.
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42.30.-d Imaging and optical processing
42.79.Vb Optical storage systems, optical disks
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Nuclear‐pumped lasing of 3He‐Xe at 2.63 μm

N. W. Jalufka

Appl. Phys. Lett. 39, 535 (1981); http://dx.doi.org/10.1063/1.92806 (2 pages) | Cited 2 times

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Direct nuclear pumping of a 3He‐Xe laser, lasing at 2.63 μm, has been achieved. Scaling of the laser output with xenon concentration, total pressure, and thermal neutron flux has been investigated. A peak power in excess of 200 W was obtained at a total pressure of 3 atm, a gas mixture consisting of 5 % xenon and 95% 3He, and a peak thermal flux of 6×1016 n/cm2 s.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
28.90.+i Other topics in nuclear engineering and nuclear power studies (restricted to new topics in section 28)
42.60.By Design of specific laser systems

Infrared pulsed opto‐acoustic spectroscopy

E. T. Nelson and C. K. N. Patel

Appl. Phys. Lett. 39, 537 (1981); http://dx.doi.org/10.1063/1.92807 (3 pages) | Cited 2 times

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We report the first pulsed opto‐acoustic spectroscopy of low loss condensed media in the infrared region. Stimulated Raman scattering in high‐pressure hydrogen gas was used for down shifting pulsed tunable dye laser radiation through first‐ and second‐order Stokes processes. Measurements of the absorption spectra of liquid ethylene in the region of 0.7–1.6 μm indicate the general applicability of this technique to other important problems.
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78.20.N- Thermo-optic effects
78.20.nb Photothermal effects
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques

Surface acoustic wave parametric oscillation in Si‐on‐LiNbO3

Yasuhiko Nakagawa, Mutuo Wakuda, and Kenichi Kobayashi

Appl. Phys. Lett. 39, 540 (1981); http://dx.doi.org/10.1063/1.92786 (3 pages)

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The observation of a surface acoustic wave parametric oscillation in Si‐on‐LiNbO3 is reported. The threshold power required for parametric oscillation was substantially reduced by the highly efficient surface acoustic wave reflectors. Experimental frequency was 130 MHz, and the conversion efficiency from the pumping to the surface acoustic waves was about −21 dB.
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68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics
62.30.+d Mechanical and elastic waves; vibrations
68.60.-p Physical properties of thin films, nonelectronic
43.35.Pt Surface waves in solids and liquids

Extreme ultraviolet absorption spectroscopy of a backlighted aluminum plasma

John C. Riordan and Jay S. Pearlman

Appl. Phys. Lett. 39, 543 (1981); http://dx.doi.org/10.1063/1.92787 (3 pages) | Cited 1 time

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We show that a cold, dense laboratory plasma can be readily characterized by extreme ultraviolet absorption spectroscopy. The plasma is produced by irradiating a thin aluminum foil with a pulsed soft x‐ray source. The same source also provides a backlighting continuum for absorption spectroscopy. Time‐integrated L‐shell spectra obtained with a grazing incidence spectrograph show collisionally broadened absorption lines of A1 IV and A1 V. The spectra provide plasma temperature and electron density measurements of ≳12 eV and 0.6×1021 cm−3, respectively.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.Kn Thermodynamics of plasmas

Characteristics of ablation plasma from planar, laser‐driven targets

J. Grun, R. Decoste, B. H. Ripin, and J. Gardner

Appl. Phys. Lett. 39, 545 (1981); http://dx.doi.org/10.1063/1.92788 (3 pages) | Cited 73 times

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The momentum, energy, and velocity characteristics of plasma ablating from planar targets irradiated by long Nd‐laser pulses (4 ns,<1014 W/cm2) are measured and the dependence of ablation parameters upon absorbed irradiance is determined. Large laser spots are used in these experiments so that the results are not sensitive to boundary effects.
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52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.70.Nc Particle measurements
52.30.-q Plasma dynamics and flow

2nd–5th electron cyclotron harmonic emission from thermal plasmas in Alcator A

P. Woskoboinikow, H. C. Praddaude, I. S. Falconer, and W. J. Mulligan

Appl. Phys. Lett. 39, 548 (1981); http://dx.doi.org/10.1063/1.92789 (3 pages) | Cited 3 times

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A sensitive submillimeter heterodyne receiver has been used to measure electron cyclotron emission at the 2nd through the 5th harmonics from thermal plasmas in Alcator A. A sensitive diagnostic of the electron energy distribution function is obtained from intensity ratios of the optically thin harmonics, in particular the small runaway fraction (∼10−6) that exists even in well thermalized Alcator A plasmas. Also the 4th and 5th harmonics are a sensitive measure of impending plasma disruption due to vessel air leaks.
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52.70.Gw Radio-frequency and microwave measurements
52.55.Fa Tokamaks, spherical tokamaks
52.55.Hc Stellarators, torsatrons, heliacs, bumpy tori, and other toroidal confinement devices
52.25.Kn Thermodynamics of plasmas
52.25.Os Emission, absorption, and scattering of electromagnetic radiation

Raman study of evaporated and sputtered GexSe1−x glass films

James E. Griffiths and W. Robert Sinclair

Appl. Phys. Lett. 39, 551 (1981); http://dx.doi.org/10.1063/1.92790 (3 pages) | Cited 7 times

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Raman spectra of thin film GexSe1−x (x = 0.1, 0.33) glasses shows them to be structurally and compositionally similar on a molecular scale whether prepared by evaporation or sputtering techniques. Their sensitivity as silver‐doped photoresist materials correlates directly with information obtained from backscattering Raman experiments on the initially prepared films. Low sensitivity in some films prepared by sputtering onto low‐temperature substrates is attributed to film contamination, probably by oxygen containing impurities or by other materials that inhibit formation of optically absorbing Ge–Se bonding networks.
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68.60.-p Physical properties of thin films, nonelectronic
81.05.Kf Glasses (including metallic glasses)
33.20.Fb Raman and Rayleigh spectra (including optical scattering)
36.40.-c Atomic and molecular clusters

Electrical conductivity of semi‐insulating polycrystalline silicon and its dependence upon oxygen content

James Ni and Emil Arnold

Appl. Phys. Lett. 39, 554 (1981); http://dx.doi.org/10.1063/1.92791 (3 pages) | Cited 31 times

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An explanation is given for the strong dependence of electrical conductivity of semi‐insulating polycrystalline silicon films on oxygen content. The proposed model assumes a shell structure such that each Si grain is surrounded by a layer of SiO2, the thickness of which is related to the oxygen content of the film. The conduction proceeds by tunneling of thermally generated carriers through the oxide layers separating adjacent grains. The model properly predicts the dependence of the low‐field conductivity on both oxygen concentration and temperature without any adjustable parameters. Evidence for oxide barrier lowering for barrier thicknesses <5 Å is observed.
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73.61.Ng Insulators
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
72.80.Ng Disordered solids

Reliability of pulsed electron‐beam‐alloyed AuGe/Pt ohmic contacts on GaAs

C. P. Lee, B. M. Welch, and J. L. Tandon

Appl. Phys. Lett. 39, 556 (1981); http://dx.doi.org/10.1063/1.92792 (3 pages) | Cited 6 times

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Reliability of pulsed electron‐beam‐alloyed AuGe/Pt ohmic contacts on GaAs has been studied and compared with thermally alloyed contacts. Electron‐beam‐alloyed contacts have excellent surface morphology and low contact resistance, but are not as reliable as thermally alloyed contacts; the specific contact resistance deteriorates with thermal aging at 250 °C. The degradation is explained by the interdiffusion and compound formation in the metals during aging.
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81.40.Rs Electrical and magnetic properties related to treatment conditions
66.30.-h Diffusion in solids

Study of ultraviolet light‐induced aging of ZnS phosphor powder by two‐beam photoacoustic spectroscopy

P. E. Simmonds and L. Eaves

Appl. Phys. Lett. 39, 558 (1981); http://dx.doi.org/10.1063/1.92793 (3 pages) | Cited 2 times

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A two‐beam photoacoustic technique is employed to monitor ultraviolet light‐induced darkening of ZnS (Mn, Cu) powder used for large‐area electroluminescent panels. The darkening process occurs for ultraviolet irradiation at wavelengths less than 345 nm. Photoacoustic measurements are made of the light‐induced change in the absorption spectrum and the influence of doping and contamination by atmospheric water on darkening rates.
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78.20.N- Thermo-optic effects
78.20.nb Photothermal effects
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors
81.40.Tv Optical and dielectric properties related to treatment conditions
07.60.-j Optical instruments and equipment

Improved techniques for growth of large‐area single‐crystal Si sheets over SiO2 using lateral epitaxy by seeded solidification

B‐Y. Tsaur, John C. C. Fan, M. W. Geis, D. J. Silversmith, and R. W. Mountain

Appl. Phys. Lett. 39, 561 (1981); http://dx.doi.org/10.1063/1.92794 (3 pages) | Cited 36 times

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Continuous single‐crystal Si sheets over SiO2 with areas of several square centimeters have been produced from poly‐Si films by the LESS technique (lateral epitaxy by seeded solidification). Seeding is achieved either with a narrow stripe opening in a recessed SiO2 layer on a single‐crystal Si substrate or with an external single‐crystal Si seed. N‐channel metal‐oxide‐semiconductor field‐effect transistors (MOSFET’s) fabricated in these films exhibit surface electron mobilities as high as 700 cm2/V s.
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68.55.-a Thin film structure and morphology
81.10.Fq Growth from melts; zone melting and refining
85.30.Tv Field effect devices
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology

Recoil oxygen implants and thermal redistribution of oxygen in through‐oxide arsenic‐implanted Si

T. J. Magee, C. Leung, H. Kawayoshi, L. J. Palkuti, B. K. Furman, C. A. Evans, L. A. Christel, J. F. Gibbons, and D. S. Day

Appl. Phys. Lett. 39, 564 (1981); http://dx.doi.org/10.1063/1.92795 (3 pages) | Cited 7 times

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The redistribution of recoil oxygen implants produced by the implantation of As ions through oxide layers on Si substrates has been investigated at annealing temperatures in the range 4000–1000 °C. Using transmission electron microscopy and secondary ion mass spectrometry profiling, it has been shown that the implanted (recoil) oxygen is rapidly gettered into residual damage structure at anneal temperatures < 900 °C. At temperatures ⩾ 1000 °C residual damage gettering sites are annihilated, releasing oxygen to migrate toward the Si surface. At the higher‐annealing temperatures, oxygen has been shown to outdiffuse rapidly into the overlying (1000 Å) oxide layer on the sample surface.
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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
66.30.J- Diffusion of impurities
61.72.J- Point defects and defect clusters

Low‐noise GaAs field‐effect transistors prepared by molecular beam epitaxy

M. Omori, T. J. Drummond, and H. Morkoç

Appl. Phys. Lett. 39, 566 (1981); http://dx.doi.org/10.1063/1.92796 (4 pages) | Cited 3 times

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The noise performance of ’’T’’ shaped Ti/W/Au gate GaAs Schottky‐barrier field‐effect transistors (FET’s) fabricated on channel layers grown by molecular beam epitaxy (MBE) is reported. The nominal gate length was about 0.7 μm with a total gate width of 250 μm. Typical noise figures and the associated gains at room temperature were 1.2 and 14 dB at 4 GHz, and 1.9 and 8.5 dB at 12 GHz. To our knowledge, these are the best results reported to date by MBE. These preliminary results, while not reaching the state of the art, do show the promise of MBE for high‐quality GaAs FET’s.
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85.30.Tv Field effect devices
72.80.Ey III-V and II-VI semiconductors
68.55.-a Thin film structure and morphology

Velocity field characteristics of minority carriers (electrons) in p‐In0.53Ga0.47As

J. Degani, R. F. Leheny, R. E. Nahory, and J. P. Heritage

Appl. Phys. Lett. 39, 569 (1981); http://dx.doi.org/10.1063/1.92797 (4 pages) | Cited 27 times

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Steady‐state velocity field characteristics for photoexcited minority electrons in p‐In0.53Ga0.47As are reported. A low‐field drift mobility of 6000 cm2/V s for ∼1017 cm−3 impurities and a high‐field drift velocity of 2.6×107 cm/s at 7.5 kv/cm are found. There is no evidence of transferred electron effects, a result which we attribute to energy scattering by holes and which leads to an enhancement of electron drift velocity.
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72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.80.Ey III-V and II-VI semiconductors

Lorentz electron microscopy of amorphous Fe40Ni40B20

J. Fidler and P. Skalicky

Appl. Phys. Lett. 39, 573 (1981); http://dx.doi.org/10.1063/1.92798 (2 pages)

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Using transmission electron microscopy we studied changes in the magnetic domain structure during annealing. At room temperature the domain structure is determined by magnetostatic effects. Cross‐tie walls are observed, and the domains vanished at fields of 25 A/cm. After heating the specimen, a two‐stage crystallization behavior occurs. The first stage (140–250 °C) is identified as primary crystallization of polycrystalline δ‐Fe Ni. Further heating (up to 400 °C) shows the formation and growth of (Fe Ni)3B spherulites. The domain structure is determined by the crystallization process. Large spherulites exhibit stripe domains and inside of nonspherulite areas magnetization ripple structures occur. Both of the crystallization centers act as pinning sites for domain walls and are sources of increased coercivity in Fe40Ni40B20 amorphous ribbons.
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75.50.Bb Fe and its alloys
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination
77.80.Dj Domain structure; hysteresis

Asymmetric current effects of 1/f noise in metal to n‐InSb contacts with an applied magnetic field

P. Vande Voorde and W. F. Love

Appl. Phys. Lett. 39, 575 (1981); http://dx.doi.org/10.1063/1.92799 (2 pages) | Cited 4 times

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Measurements of 1/f noise in metal to n‐InSb contacts at 75 K are reported. This is observed to be sensitive to current direction and to external magnetic fields.
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72.70.+m Noise processes and phenomena
73.40.Ns Metal-nonmetal contacts
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