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30 Jan 1989

Volume 54, Issue 5, pp. 403-471


Mode locking and Q switching of a diode laser pumped neodymium‐doped yttrium lithium fluoride laser

G. T. Maker and A. I. Ferguson

Appl. Phys. Lett. 54, 403 (1989); http://dx.doi.org/10.1063/1.100976 (3 pages) | Cited 8 times

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We have developed a mode‐locked, diode pumped, neodymium‐doped yttrium lithium fluoride (Nd:YLF) laser operating at 1.053 μm. The laser produces pulses of 18 ps duration at an average power level of 12 mW. When Q switched the duration of the pulse train was 140 ns, giving rise to peak powers of 15 kW.
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42.60.Fc Modulation, tuning, and mode locking
42.55.Rz Doped-insulator lasers and other solid state lasers
42.55.Px Semiconductor lasers; laser diodes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Improvements in the differential phase shift of magneto‐optic waveguides by loading with high refractive index overlayers

H. Inuzuka, Y. Okamura, and S. Yamamoto

Appl. Phys. Lett. 54, 406 (1989); http://dx.doi.org/10.1063/1.101567 (3 pages) | Cited 2 times

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Experimental results are presented for a nonreciprocal phase shift of vertically polarized waves in four‐layer magneto‐optic rib waveguides. The structure consists of a high refractive index nonmagnetic layer of titanium oxide on top of a magneto‐optic film (a lanthanum and gallium substituted yttrium iron garnet film on a gadolinium gallium garnet substrate) to improve differential phase characteristics. The difference of phase constants for waves traveling in opposite directions is evaluated by observing the variation in the polarization coupled out of a straight waveguide when simultaneously exciting both horizontally and vertically polarized waves with equal amplitudes and phases. The phase shift difference varies with the thickness of the nonmagnetic film, and is larger than that of a previous three‐layer waveguide in the overlayer thickness range 0.15–0.45 μm. The maximum phase shift obtained is 2.5 times as large as that of uncoated waveguides.
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42.79.Gn Optical waveguides and couplers
78.20.Ls Magneto-optical effects
85.70.Sq Magnetooptical devices
78.66.Sq Composite materials

Above‐threshold analysis of ideal Y‐junction semiconductor laser arrays

William Streifer, David F. Welch, Josef Berger, and Don R. Scifres

Appl. Phys. Lett. 54, 409 (1989); http://dx.doi.org/10.1063/1.100959 (2 pages)

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An analysis of ideal Y‐junction arrays above threshold shows that the radiation patterns deteriorate and the array begins to lase in more than one mode with increasing output power.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.82.-m Integrated optics

Generation of tunable 9 femtosecond optical pulses in the near infrared

P. C. Becker, H. L. Fragnito, R. L. Fork, F. A. Beisser, and C. V. Shank

Appl. Phys. Lett. 54, 411 (1989); http://dx.doi.org/10.1063/1.100936 (2 pages) | Cited 19 times

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We report the generation of tunable femtosecond pulses in the 800–850 nm range. These pulses were obtained by generating a femtosecond continuum and selectively amplifying a portion of that continuum. The amplified femtosecond infrared pulses thus obtained were then compressed to a duration of 9 fs by a fiber followed by a grating and prism sequence.
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42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
42.55.Rz Doped-insulator lasers and other solid state lasers
42.81.Dp Propagation, scattering, and losses; solitons

Ion mixing of metal/Al bilayers near 77 K

E. Ma, T. W. Workman, W. L. Johnson, and M‐A. Nicolet

Appl. Phys. Lett. 54, 413 (1989); http://dx.doi.org/10.1063/1.100937 (3 pages) | Cited 25 times

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The efficiency of interfacial ion mixing is measured for metal/Al (metal=Ti, Cr, Ni, and Mo) thin‐film bilayers irradiated with 285 keV Xe+ ions near 77 K. The results indicate that, as a group, mixing of 3d‐metal/Al pairs irradiated by Xe can be explained by neither a pure binary collision cascade nor a pure thermal spike model. Such a situation should exist; that it should be found at the average atomic numbers of the present bilayers is consistent with recent theoretical predictions.
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61.80.Jh Ion radiation effects
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
68.35.Fx Diffusion; interface formation
66.30.J- Diffusion of impurities

In situ characterization of diamond nucleation and growth

David N. Belton, Stephen J. Harris, Steven J. Schmieg, Anita M. Weiner, and Thomas A. Perry

Appl. Phys. Lett. 54, 416 (1989); http://dx.doi.org/10.1063/1.100938 (2 pages) | Cited 116 times

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Filament‐assisted chemical vapor deposition (CVD) diamond film growth on Si(100) was studied using x‐ray photoelectron spectroscopy (XPS) to examine the sample at selected intervals during the nucleation and growth processes. The sample was transferred under vacuum from the growth chamber to the attached XPS analysis chamber without exposure to air. Before growth XPS showed that the Si sample is covered by a layer of SiO2 and carbonaceous residue; however, after 15 min of growth both of these substances are removed and replaced by a distinct SiC layer [Si(2p)=100.3 eV and C(1s)=282.7 eV].
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81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
78.30.Hv Other nonmetallic inorganics

Stimulated emission by ballistic electrons in semiconducting superlattices

Mordechai Botton and Amiram Ron

Appl. Phys. Lett. 54, 418 (1989); http://dx.doi.org/10.1063/1.100939 (3 pages) | Cited 2 times

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We investigate the radiation due to transitions of ballistic electrons in a superlattice. The equations of motion for the populations of photons and electrons are used to analyze the system both as an amplifier and as an oscillator. We then calculate the gain of the system and the threshold current needed to overcome electromagnetic losses. Finally, we compare our proposed infrared active system with other existing lasers.
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72.20.-i Conductivity phenomena in semiconductors and insulators
78.45.+h Stimulated emission
85.30.-z Semiconductor devices
79.90.+b Other topics in electron and ion emission by liquids and solids and impact phenomena (restricted to new topics in section 79)

Oxidation of silicon with a 5 eV O− beam

M. H. Hecht, O. J. Orient, A. Chutjian, and R. P. Vasquez

Appl. Phys. Lett. 54, 421 (1989); http://dx.doi.org/10.1063/1.101456 (3 pages) | Cited 9 times

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A silicon wafer has been oxidized at room temperature in vacuum using a pure, ground‐state beam of O− ions. The beam was of sufficiently low energy that no displacement damage or implantation was energetically possible. The resulting SiO2 films were analyzed with x‐ray photoelectron spectroscopy. A logarithmic dependence of oxide thickness on dose was observed, with an extrapolated oxidation efficiency of unity for the clean silicon surface. A distinct initial oxidation phase was observed, with an anomalously high level of silicon suboxides. In addition, the valence‐band offset between the silicon and the oxide was unusually small, suggesting a large interfacial dipole.
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81.65.-b Surface treatments
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
68.35.Fx Diffusion; interface formation
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Shallow impurity neutralization in GaP by atomic hydrogen

Mandeep Singh and Jörg Weber

Appl. Phys. Lett. 54, 424 (1989); http://dx.doi.org/10.1063/1.100940 (3 pages) | Cited 36 times

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Hydrogen neutralizes both donors and acceptors in GaP by a mechanism that is independent of the site of the impurity in the lattice, but is dependent on the identity of the impurity. Hydrogen also passivates an isoelectronic trap nitrogen, a phenomenon first encountered here in GaP. We propose a simple model for the NH binding based on a polarized N−H+ bond. This model accounts for the relative passivation of a series of NN pairs, where the passivation depends critically on the NN separation distance. Our results also support the recently revised correlation of spectral lines with NN pairs of varying separations.
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71.55.Eq III-V semiconductors
61.72.Bb Theories and models of crystal defects
78.55.Cr III-V semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Scanning tunneling microscope study of microcrystalline silicon surfaces in air

Ichiro Tanaka, Fukunobu Osaka, Takashi Kato, Yoshifumi Katayama, Shin‐ichi Muramatsu, and Toshikazu Shimada

Appl. Phys. Lett. 54, 427 (1989); http://dx.doi.org/10.1063/1.100941 (3 pages) | Cited 6 times

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Surfaces of microcrystalline silicon films prepared by the glow discharge method have been investigated by a scanning tunneling microscope (STM) in air. Grain‐like structures of 30–80 nm size which correspond to transmission electron microscope data have been observed. The film surface was found to be geometrically rather flat but the structure was observed electrically, that is, the resistivity seemed to be inhomogeneous due to preferential oxidation. Also, degradation of STM images of a HF‐etched microcrystalline silicon surface has been observed for the first time.
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07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination
68.35.B- Structure of clean surfaces (and surface reconstruction)
73.25.+i Surface conductivity and carrier phenomena
68.55.-a Thin film structure and morphology

Rapid thermal oxidation of thin nitride/oxide stacked layer

W. T. Chang, D. K. Shih, D. L. Kwong, Y. Zhou, and S. Lee

Appl. Phys. Lett. 54, 430 (1989); http://dx.doi.org/10.1063/1.100942 (3 pages) | Cited 9 times

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The effects of rapid thermal oxidation (RTO) on the chemical vapor deposited nitride/oxide layer for thin gate dielectrics were studied. Successful growth of a top oxide of ∼25 Å was confirmed using x‐ray photoelectron spectroscopy and no punchthrough of the chemical vapor deposited nitride was observed for a nitride thickness of 60 Å. Changes in electrical properties after RTO were studied using current‐voltage and charge‐to‐breakdown measurements. Results indicate that the top oxide reduces the leakage current under positive gate bias and increases the leakage current at high fields for negative gate bias. In addition, the charge to breakdown of the layer is increased after RTO.
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81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.65.-b Surface treatments
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
73.61.Ng Insulators

Molecular beam epitaxy of GaAs/AlGaAs quantum wells on channeled substrates

H. P. Meier, E. Van Gieson, W. Walter, C. Harder, M. Krahl, and D. Bimberg

Appl. Phys. Lett. 54, 433 (1989); http://dx.doi.org/10.1063/1.100943 (3 pages) | Cited 18 times

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GaAs/AlGaAs quantum wells (QWs) were grown by molecular beam epitaxy on GaAs (100) substrates patterned with ridges and grooves in the [011] direction. Low‐temperature cathodoluminescence was used to measure the Al fraction and QW thickness on top of the ridges and grooves as a function of ridge and groove width. Surface diffusion during growth depletes Ga from the side facets while increasing the incorporation of Ga on the (100) sections of ridges and grooves. The QW thickness on top of a ridge grown at 710 °C increases from 72 to 95 Å, and the Al fraction x decreases from x=0.33 to x=0.29 as the ridge width is narrowed from 30 to 4 μm. Graded refractive index separate confinement heterostructure lasers with nominally 70 Å QWs and Al0.2Ga0.8As barriers were grown on patterned substrates at 695 and 725 °C. Lasers fabricated on the overgrown 4‐μm‐wide ridges have a 20 meV decrease in emission energy compared to laser diodes on 30 μm ridges.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
42.55.Px Semiconductor lasers; laser diodes
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
78.60.Hk Cathodoluminescence, ionoluminescence

Cathodoluminescence study of substrate offset effects on interface step structures of quantum wells

K. Wada, A. Kozen, Y. Hasumi, and J. Temmyo

Appl. Phys. Lett. 54, 436 (1989); http://dx.doi.org/10.1063/1.100944 (3 pages) | Cited 14 times

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The interface structures of single quantum wells grown on vicinal (100) substrates with a controlled offset 0.2° are studied by cathodoluminescence microscopy. Bright and dark stripe patterns are periodically observed in monochromatic images of the single quantum wells and the stripes replicate stair‐like stepped interfaces. It is further shown that the observed terrace width is several times larger than the average interstep distance of monolayer steps calculated from the offset angle and that the step height is not one monolayer. Based on the results, a new interface structure model has been proposed that takes the offset angle into account. Finally, it is shown that employing growth interruption during epitaxial growth as an interface smoothing technique has limitations.
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78.60.Hk Cathodoluminescence, ionoluminescence
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Light‐induced changes of gap‐state profile in phosphorus‐doped hydrogenated amorphous silicon

Hideyo Okushi, Tatsuya Furui, Ratnabali Banerjee, and Kazunobu Tanaka

Appl. Phys. Lett. 54, 439 (1989); http://dx.doi.org/10.1063/1.100945 (3 pages)

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We have determined the gap‐state profiles of phosphorus‐doped hydrogenated amorphous silicon before and after light soaking in a broader energy range [0.25–1.50 eV below the conduction‐band edge (Ec) ] by using several variations of isothermal capacitance transient spectroscopy. It is found that gap states are created in the range of 0.25–0.35 eV below Ec, which are attributed to 31P‐related hyperfine electron‐spin‐resonance centers.
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71.55.Ht Other nonmetals
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Optical investigation of atomic steps in ultrathin InGaAs/InP quantum wells grown by vapor levitation epitaxy

P. C. Morais, H. M. Cox, P. L. Bastos, D. M. Hwang, J. M. Worlock, E. Yablonovitch, and R. E. Nahory

Appl. Phys. Lett. 54, 442 (1989); http://dx.doi.org/10.1063/1.100946 (3 pages) | Cited 31 times

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Ultrathin InGaAs/InP single quantum well structures, grown by chloride transport vapor levitation epitaxy, have been investigated by low‐temperature photoluminescence (PL). Well‐resolved multiple peaks are observed in the PL spectra, instead of an expected single peak. We attribute this to monolayer (a0/2=2.93 Å) variations in quantum well (QW) thickness. Separate peak positions for QW thicknesses corresponding to 2–6 monolayers have been determined, providing an unambiguous thickness calibration for spectral shifts due to quantum confinement. The PL peak corresponding to two monolayers occurs at 1.314 eV, corresponding to an energy shift of 524 meV. Experimental data agree very well with a simple effective mass theory.
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81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
78.66.Hf II-VI semiconductors

Application of the Williams–Watts decay law to DX center capture and emission kinetics

A. C. Campbell and B. G. Streetman

Appl. Phys. Lett. 54, 445 (1989); http://dx.doi.org/10.1063/1.100947 (3 pages) | Cited 24 times

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The Williams–Watts or stretched exponential decay of the form A(t)=exp[−(t/τ)β] and variations of this form are compared to the capture and emission kinetics of the DX center observed by a number of authors. It is found that the time and temperature behavior of the DX center capture and emission characteristics can be reproduced with a thermally activated time constant τ and a linear dependence of β on temperature. Activation energies, lattice vibration frequencies, and models of implicit distributions of activation energies are compared to values previously found in the literature. Consistency is found between parameters for both capture and emission, and implications of this model are discussed.
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71.55.Eq III-V semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.80.Ng Disordered solids
66.30.J- Diffusion of impurities

Sequential nature of damage annealing and activation in implanted GaAs

J. L. Tandon, J. H. Madok, I. S. Leybovich, G. Bai, and M‐A. Nicolet

Appl. Phys. Lett. 54, 448 (1989); http://dx.doi.org/10.1063/1.100948 (3 pages) | Cited 3 times

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Rapid thermal processing of implanted GaAs reveals a definitive sequence in the damage annealing and the electrical activation of ions. Removal of implantation‐induced damage and restoration of GaAs crystallinity occurs first. Irrespective of implanted species, at this stage the GaAs is n‐type and highly resistive with almost ideal values of electron mobility. Electrical activation is achieved next when, in a narrow anneal temperature window, the material becomes n‐ or p‐type, or remains semi‐insulating, commensurate to the chemical nature of the implanted ion. Such a two‐step sequence in the electrical doping of GaAs by ion implantation may be unique of GaAs and other compound semiconductors.
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61.80.Jh Ion radiation effects
61.72.Bb Theories and models of crystal defects
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
72.20.Fr Low-field transport and mobility; piezoresistance

Displacement damage equivalent to dose in silicon devices

C. J. Dale, P. W. Marshall, G. P. Summers, E. A. Wolicki, and E. A. Burke

Appl. Phys. Lett. 54, 451 (1989); http://dx.doi.org/10.1063/1.100949 (3 pages) | Cited 8 times

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Particle‐induced displacement damage effects in silicon bipolar transistors, including those due to electrons and to fission neutrons, are correlated on the basis of the nonionizing energy deposited in the lattice by the primary knock‐on atoms. Deviations from linearity between damage effects and energy deposition are in a direction opposite to those expected from defect cluster models but can be accounted for in terms of the fraction of vacancy‐interstitial pairs initially formed that survive recombination.
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61.80.Fe Electron and positron radiation effects
61.80.Hg Neutron radiation effects
85.30.Pq Bipolar transistors
61.72.jd Vacancies
61.72.jj Interstitials

Gain recovery time of traveling‐wave semiconductor optical amplifiers

G. Eisenstein, R. S. Tucker, J. M. Wiesenfeld, P. B. Hansen, G. Raybon, B. C. Johnson, T. J. Bridges, F. G. Storz, and C. A. Burrus

Appl. Phys. Lett. 54, 454 (1989); http://dx.doi.org/10.1063/1.100950 (3 pages) | Cited 16 times

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We propose a mechanism which may shorten the gain recovery time in semiconductor optical amplifiers. The mechanism is carrier diffusion from nearby carrier storage regions (carrier reservoirs), which enhances the carrier recovery process in the active region and consequently reduces the gain recovery time. Bias‐independent recovery times as short at 100 ps are demonstrated in a 1.3‐μm traveling‐wave amplifier.
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07.60.-j Optical instruments and equipment
42.79.-e Optical elements, devices, and systems
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
85.60.-q Optoelectronic devices
78.20.Jq Electro-optical effects

Transport properties of two‐dimensional electron gas systems in delta‐doped Si:In0.53Ga0.47As grown by organometallic chemical vapor deposition

W‐P. Hong, F. DeRosa, R. Bhat, S. J. Allen, and J. R. Hayes

Appl. Phys. Lett. 54, 457 (1989); http://dx.doi.org/10.1063/1.100951 (3 pages) | Cited 12 times

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We have investigated the transport properties of a two‐dimensional electron gas formed in delta‐doped In0.53 Ga0.47 As grown by metalorganic chemical vapor deposition technique. Very high free‐electron concentrations of 1.4×1013 and 9.6×1012 cm−2 have been obtained at 300 and 77 K, respectively. Hall mobilities of 9300 and 14 600 cm2 /V s were measured with carrier concentrations of 3.7×1012 and 3.0×1012 cm−2 at 300 and 77 K, respectively. This is a factor of 3 higher than is expected for homogeneously doped materials having a similar doping. Schubnikov–de Haas oscillations confirmed the two‐dimensional nature of the electronic structure in these delta‐doped materials, and electron effective masses were determined from cyclotron resonance measurements.
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72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.20.My Galvanomagnetic and other magnetotransport effects
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
72.80.Ey III-V and II-VI semiconductors

Negative transconductance and negative differential resistance in a grid‐gate modulation‐doped field‐effect transistor

K. Ismail, W. Chu, A. Yen, D. A. Antoniadis, and Henry I. Smith

Appl. Phys. Lett. 54, 460 (1989); http://dx.doi.org/10.1063/1.100952 (3 pages) | Cited 49 times

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We report on transport measurements in grid‐gate lateral‐surface‐superlattice (LSSL) field‐effect transistors on a modulation‐doped GaAs/AlGaAs heterostructure. The LSSL is created by a 0.2 μm period Ti/Au grid on top of the AlGaAs layer, which presents a tunable, two‐dimensional periodic potential modulation to the electrons traveling from source to drain. Current measurements at 4.2 K as a function of gate bias exhibit negative transconductance at a fixed drain bias below 15 mV, providing evidence of a superlattice effect (i.e., coherent back‐diffraction). In addition, negative differential resistance is observed at a fixed gate bias and a drain bias around 100 mV, which could be a manifestation of sequential resonant tunneling.
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85.30.Tv Field effect devices
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.61.Ey III-V semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

New gettering using misfit dislocations in homoepitaxial wafers with heavily boron‐doped silicon substrates

H. Kikuchi, M. Kitakata, F. Toyokawa, and M. Mikami

Appl. Phys. Lett. 54, 463 (1989); http://dx.doi.org/10.1063/1.100953 (3 pages) | Cited 6 times

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The gettering mechanism due to misfit dislocations in P/P+ epitaxial wafers is clarified for copper‐diffused epitaxial wafers. The epilayer thickness of the sample is 2.2 μm and the substrate resistivity of the sample is 0.0015–0.002 Ω cm. It is dipped in a Cu(NO3 )2 ‐HF solution and annealed at 900 °C for 30 min. The in‐depth Cu profile obtained by secondary‐ion mass spectroscopy shows a distinctive peak at the P+ ‐substrate side in the vicinity of the epi/sub interface. This peak coincides with that of dislocation density for their location in depth. Furthermore, from energy dispersive spectroscopy observation the diffused copper is found to be effectively gettered at misfit dislocations as copper silicide from moiré fringe.
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61.72.Bb Theories and models of crystal defects
66.30.J- Diffusion of impurities
85.40.Hp Lithography, masks and pattern transfer
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Preparation of superconducting Bi‐Sr‐Ca‐Cu‐O thin films by sequential electron beam evaporation and oxygen annealing

J. Steinbeck, B‐Y. Tsaur, A. C. Anderson, and A. J. Strauss

Appl. Phys. Lett. 54, 466 (1989); http://dx.doi.org/10.1063/1.101457 (3 pages) | Cited 7 times

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Superconducting films with nominal composition Bi2Sr2Ca1Cu2Ox have been prepared on 〈100〉 MgO substrates by sequential electron beam evaporation of Cu, Bi, and Sr2/3 Ca1/3 F2, followed by annealing in flowing wet, then dry, O2. X‐ray diffraction data show that the films contain the two Bi‐Sr‐Ca‐Cu‐O phases that have been identified in the literature as a superconducting phase with c∼31 Å and a semiconducting phase with c∼24 Å. Both phases are strongly textured with the c axis perpendicular to the substrate. For the best film, which was annealed at 870 °C for 30 min, zero resistance was observed at 90 K, and the critical current density increased from 0.8×105 A/cm2 at 77 K to 2.3×105 A/cm2 at 4.2 K.
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74.78.-w Superconducting films and low-dimensional structures
74.70.-b Superconducting materials other than cuprates
74.25.Sv Critical currents
68.55.Nq Composition and phase identification

Spectral characteristics of plasma emission during ArF excimer laser ablation of YBa2Cu3O7

T. J. Geyer and W. A. Weimer

Appl. Phys. Lett. 54, 469 (1989); http://dx.doi.org/10.1063/1.101555 (3 pages) | Cited 23 times

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In order to characterize the laser ablation process as it relates to the deposition of high Tc superconducting thin films, optical emission spectra produced during ArF excimer laser ablation of the high Tc superconductor YBa2Cu3O7 were studied. The population of excited states within the gas phase blow‐off material depends strongly on excimer laser fluence at 193 nm. Ablation using relatively low excimer laser fluences produces a significant fraction of YO in the gas phase. The plasmas derived from ablation of targets made from the high Tc material are similar to plasmas observed from ablation of the individual components BaCO3, CuO, and Y2O3.
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74.78.-w Superconducting films and low-dimensional structures
79.20.Ds Laser-beam impact phenomena
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
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