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16 Apr 2001

Volume 78, Issue 16, pp. 2267-2404

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Highly conductive epitaxial CdO thin films prepared by pulsed laser deposition

M. Yan, M. Lane, C. R. Kannewurf, and R. P. H. Chang

Appl. Phys. Lett. 78, 2342 (2001); http://dx.doi.org/10.1063/1.1365410 (3 pages) | Cited 84 times

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Epitaxial growth of both pure and doped CdO thin films has been achieved on MgO (111) substrates using pulsed laser deposition. A maximum conductivity of 42 000 S/cm with mobility of 609 cm2/V s is achieved when the CdO epitaxial film is doped with 2.5% Sn. The pure CdO epitaxial film has a band gap of 2.4 eV. The band gap increases with doping and reaches a maximum of 2.87 eV when the doping level is 6.2%. Both grain boundary scattering and ionized impurity scattering are found to contribute to the mobility of CdO films. © 2001 American Institute of Physics.
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81.15.Fg Pulsed laser ablation deposition
81.05.Dz II-VI semiconductors
73.61.Ga II-VI semiconductors
72.80.Ey III-V and II-VI semiconductors
68.55.-a Thin film structure and morphology
71.20.Nr Semiconductor compounds
72.20.Fr Low-field transport and mobility; piezoresistance
73.50.Dn Low-field transport and mobility; piezoresistance
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Surface morphology evolution in highly mismatched Sb-graded buffer layers on GaAs

Eric B. Chen, David C. Paine, Parvez N. Uppal, Kirby Nichols, and John S. Ahearn

Appl. Phys. Lett. 78, 2345 (2001); http://dx.doi.org/10.1063/1.1366361 (3 pages) | Cited 2 times

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Ternary GaAs1−ySby and quaternary Al0.5Ga0.5As1−ySby compositionally step-graded buffer structures graded to a 4.6% mismatch on GaAs were evaluated by transmission electron microscopy. Cross-sectional bright field imaging (g = 004) revealed the presence of compositional modulations parallel to the (001) interface with a period of 1–2 nm that were used to establish the morphology of the growth surface during buffer layer deposition. Analysis of the Sb-graded ternary structures shows that the growth surface remained planar with a maximum peak-to-valley height of 4.4±0.6 nm located near the topmost layer. A threading dislocation density of 108–109 cm−2 was measured in both types of buffer layers and an improvement in peak-to-valley amplitude (2.3±0.5 nm vs 4.4±0.6 nm) was observed in the Al-containing quaternary alloys. © 2001 American Institute of Physics.
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61.72.Lk Linear defects: dislocations, disclinations
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.-a Thin film structure and morphology
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Angular momentum and energy transferred through ferromagnetic resonance

Albrecht Jander, John Moreland, and Pavel Kabos

Appl. Phys. Lett. 78, 2348 (2001); http://dx.doi.org/10.1063/1.1361095 (3 pages) | Cited 4 times

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We show that ferromagnetic resonance (FMR) selectively transfers angular momentum and energy from a microwave field to the lattice as measurable torque and heat. The expected torque and absorbed power are derived classically in terms of Landau–Lifshitz dynamics, including demagnetizing field effects. The torque is also described as a photon absorption process, in which the absorbed photons carry both energy and angular momentum. FMR data are shown for a thin NiFe film deposited on a micromechanical cantilever detector that measures both torque and heat under nearly identical conditions. © 2001 American Institute of Physics.
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76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Bb Fe and its alloys

Suppression of superconductivity by crystallographic defects in epitaxial Sr2RuO4 films

Mark A. Zurbuchen, Yunfa Jia, Stacy Knapp, Altaf H. Carim, Darrell G. Schlom, Ling-Nian Zou, and Ying Liu

Appl. Phys. Lett. 78, 2351 (2001); http://dx.doi.org/10.1063/1.1364659 (3 pages) | Cited 10 times

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Epitaxial Sr2RuO4 thin films grown by pulsed-laser deposition from high-purity (99.98%) Sr2RuO4 targets on (001) LaAlO3 were found to be not superconducting down to 0.4 K. Structural disorder is believed to be responsible. A correlation was observed between higher resistivity ratios in electrical transport measurements and narrower x-ray diffraction rocking curve widths of the Sr2RuO4 films. High-resolution transmission electron microscopy revealed that the dominant structural defects, i.e., the defects leading to the observed variation in rocking curve widths in the films, are {011} planar defects, with a spacing comparable to the in-plane superconducting coherence length of Sr2RuO4. These results imply that minimizing structural disorder is the key remaining challenge to achieving superconducting Sr2RuO4 films. © 2001 American Institute of Physics.
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74.78.-w Superconducting films and low-dimensional structures
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Dependence of dielectric properties on internal stresses in epitaxial barium strontium titanate thin films

Hao Li, A. L. Roytburd, S. P. Alpay, T. D. Tran, L. Salamanca-Riba, and R. Ramesh

Appl. Phys. Lett. 78, 2354 (2001); http://dx.doi.org/10.1063/1.1359141 (3 pages) | Cited 83 times

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A series of heteroepitaxial BaxSr1−xTiO3 thin films with composition x = 0.50 were deposited on (001) MgO substrates by pulsed-laser deposition. The thickness of the films was varied from 14 to 500 nm to produce a systematically decreasing level of in-plane tensile stresses. The microstructural and crystallographic features of the films were determined via transmission electron microscopy and x-ray diffraction. A theoretical treatment of the in-plane misfit strain as a function of film thickness is in agreement with the measured out-of-plane lattice parameters. Electrical measurements indicate a drop in the dielectric constant from 2350 for highly stressed thin films to 1700 for relaxed thicker films. The variation in the dielectric constant with the misfit strain is in accordance with a thermodynamic model developed. The relationship between the dielectric constant and electric field is also described by extending the thermodynamic model and taking the effect of electric field into account. A new definition of tunability is adopted to study the effect of strain on tunability. © 2001 American Institute of Physics.
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
68.60.Bs Mechanical and acoustical properties
77.22.Ch Permittivity (dielectric function)

Electrical and materials properties of ZrO2 gate dielectrics grown by atomic layer chemical vapor deposition

Charles M. Perkins, Baylor B. Triplett, Paul C. McIntyre, Krishna C. Saraswat, Suvi Haukka, and Marko Tuominen

Appl. Phys. Lett. 78, 2357 (2001); http://dx.doi.org/10.1063/1.1362331 (3 pages) | Cited 98 times

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Structural and electrical properties of gate stack structures containing ZrO2 dielectrics were investigated. The ZrO2 films were deposited by atomic layer chemical vapor deposition (ALCVD) after different substrate preparations. The structure, composition, and interfacial characteristics of these gate stacks were examined using cross-sectional transmission electron microscopy and x-ray photoelectron spectroscopy. The ZrO2 films were polycrystalline with either a cubic or tetragonal crystal structure. An amorphous interfacial layer with a moderate dielectric constant formed between the ZrO2 layer and the substrate during ALCVD growth on chemical oxide-terminated silicon. Gate stacks with a measured equivalent oxide thickness (EOT) of 1.3 nm showed leakage values of 10−5 A/cm2 at a bias of −1 V from flatband, which is significantly less than that seen with SiO2 dielectrics of similar EOT. A hysteresis of 8–10 mV was seen for ±2 V sweeps while a midgap interface state density (Dit) of ∼ 3×1011 states/cm eV was determined from comparisons of measured and ideal capacitance curves. © 2001 American Institute of Physics.
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77.55.-g Dielectric thin films
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
79.60.Dp Adsorbed layers and thin films
61.66.Fn Inorganic compounds
77.22.Ch Permittivity (dielectric function)
73.20.At Surface states, band structure, electron density of states
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Ferroelectric and electromechanical properties of poly(vinylidene-fluoride–trifluoroethylene–chlorotrifluoroethylene) terpolymer

Haisheng Xu, Z.-Y. Cheng, Dana Olson, T. Mai, Q. M. Zhang, and G. Kavarnos

Appl. Phys. Lett. 78, 2360 (2001); http://dx.doi.org/10.1063/1.1358847 (3 pages) | Cited 66 times

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This letter reports the ferroelectric and electromechanical properties of a class of ferroelectric polymer, poly(vinylidene-fluoride–trifluoroethylene–chlorotrifluoroethylene) terpolymer, which exhibits a slim polarization hysteresis loop and a high electrostrictive strain at room temperature. The dielectric and polarization behaviors of this terpolymer are typical of the ferroelectric relaxor. The x-ray and Fourier transform infrared results reveal that the random incorporation of bulky chlorotrifluoroethylene (CTFE) ter-monomers into polymer chains causes disordering of the ferroelectric phase. Furthermore, CTFE also acts as random defect fields which randomize the inter- and intrachain polar coupling, resulting in the observed ferroelectric relaxor behavior. © 2001 American Institute of Physics.
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77.80.-e Ferroelectricity and antiferroelectricity
77.84.Jd Polymers; organic compounds
77.22.Ej Polarization and depolarization
77.65.Fs Electromechanical resonance; quartz resonators
77.22.Gm Dielectric loss and relaxation
77.80.Dj Domain structure; hysteresis
77.65.Bn Piezoelectric and electrostrictive constants

Effect of microstructures on the microwave dielectric properties of ZrTiO4 thin films

Yongjo Kim, Jeongmin Oh, Tae-Gon Kim, and Byungwoo Park

Appl. Phys. Lett. 78, 2363 (2001); http://dx.doi.org/10.1063/1.1366359 (3 pages) | Cited 27 times

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To obtain various paraelectric ZrTiO4 thin-film microstructures, the films were synthesized at different deposition temperatures using rf magnetron sputtering. Both the dielectric losses (tan δ) and dielectric constants (ϵ) of the ZrTiO4 thin films were measured up to 6 GHz using a circular-patch capacitor geometry. The films showed enhanced crystallinity with increasing deposition temperature, as determined from the x-ray diffraction peak widths at various scattering vectors. The microwave dielectric losses correlated very well with the level of crystallinity or strain, while the dielectric constants did not alter significantly. © 2001 American Institute of Physics.
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77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.15.Cd Deposition by sputtering
68.55.-a Thin film structure and morphology
77.22.Gm Dielectric loss and relaxation
77.22.Ch Permittivity (dielectric function)
61.72.-y Defects and impurities in crystals; microstructure
68.60.Bs Mechanical and acoustical properties
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Investigation of quantum-confinement effect and Stokes shift in strained Ga1−xInxN/GaN double quantum wells by spectroscopic ellipsometry and photoluminescence

Myoung Hee Lee, Kwang Joo Kim, and Eunsoon Oh

Appl. Phys. Lett. 78, 2366 (2001); http://dx.doi.org/10.1063/1.1355987 (3 pages) | Cited 5 times

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The evolution of the optical absorption and emission properties of strained Ga1−xInxN/GaN double quantum wells grown on (0001)-oriented sapphire substrates with varying well width has been investigated by spectroscopic ellipsometry (SE) and photoluminescence (PL). The SE result shows that the band-gap absorption energy of the wells shifts to higher energies as the well width decreases, indicating a quantum-confinement effect. The decreasing trend agrees with the result of one-dimensional square-well potential calculations. The PL result shows a Stokes shift of the emission edge from the corresponding absorption edge, attributable to the combined effects of the strain-induced piezoelectric potential and the In-fluctuation potential in the well. The blueshift of the emission edge with increasing PL excitation density further supports the existence of a strong piezoelectric field in the well. © 2001 American Institute of Physics.
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78.67.De Quantum wells
78.55.Cr III-V semiconductors
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
78.40.Fy Semiconductors
81.07.St Quantum wells
81.05.Ea III-V semiconductors
77.65.Ly Strain-induced piezoelectric fields

Observation of negative differential resistance of a trench-type narrow InGaAs quantum-wire field-effect transistor on a (311)A InP substrate

Takeyoshi Sugaya, Mutsuo Ogura, Yoshinobu Sugiyama, Kazuyuki Matsumoto, Kenji Yonei, and Kee-Youn Jang

Appl. Phys. Lett. 78, 2369 (2001); http://dx.doi.org/10.1063/1.1365947 (3 pages) | Cited 7 times

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A trench-type narrow InGaAs quantum-wire field-effect transistor (QWR–FET) with a cross section of 8×25 nm has been fabricated on a (311)A InP V-grooved substrate by molecular-beam epitaxy. The trench-type InGaAs QWR–FET has normal static characteristics at room temperature, and demonstrates clear negative differential resistance characteristics at 40 K with a high peak-to-valley current ratio (PVR=4.3) and a low onset voltage of 0.12 V. © 2001 American Institute of Physics.
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73.61.Ey III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
73.50.Fq High-field and nonlinear effects
73.63.Nm Quantum wires
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
85.30.Tv Field effect devices

Excellent electric properties of free-standing InAs membranes

Hiroshi Yamaguchi, Remi Dreyfus, Yoshiro Hirayama, and Sen Miyashita

Appl. Phys. Lett. 78, 2372 (2001); http://dx.doi.org/10.1063/1.1365946 (3 pages) | Cited 17 times

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We fabricated semiconducting free-standing-beam and Hall-bar structures with a high slenderness ratio, a minimum thickness of 50 nm, and a typical length of several tens of microns using InAs membranes processed from InAs/GaAs heterostructures. These structures showed clear electric conductivity without any intentional doping. We obtained the carrier concentration and mobility by means of standard Hall measurements, thus confirming that both parameters were much larger than those of as-grown heterostructure samples. These results indicate that this material system is promising for micro/nanoelectromechanical system applications. © 2001 American Institute of Physics.
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73.61.Ey III-V semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)

Growth and control of nanoprotrusions on iridium field emitters

Babu R. Chalamala, Robert H. Reuss, and Kenneth A. Dean

Appl. Phys. Lett. 78, 2375 (2001); http://dx.doi.org/10.1063/1.1364662 (3 pages) | Cited 6 times

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We report on the direct observation of the growth of nanoprotrusions on iridium field-emission tips. For clean, protrusion-free field emitters, the field emission originated from crystal planes with low-work-function values. However, with continuous operation, we observed the growth of nanoprotrusions on crystalline planes where there was initially no detectable emission. The protrusions were estimated to be approximately 2–3 nm in diameter and 5–15 nm in height. Protrusion growth led to an increase in field-emission current by several orders of magnitude. However, the tips were destroyed when operated with sustained emission current values greater than 10 μA. We found that stable operation and control of protrusion growth can be achieved by either progressively reducing the anode voltage or by adding a series resistor. © 2001 American Institute of Physics.
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85.45.Db Field emitters and arrays, cold electron emitters
79.70.+q Field emission, ionization, evaporation, and desorption
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Organic light-emitting devices with saturated red emission using 6,13-diphenylpentacene

L. C. Picciolo, H. Murata, and Z. H. Kafafi

Appl. Phys. Lett. 78, 2378 (2001); http://dx.doi.org/10.1063/1.1362259 (3 pages) | Cited 48 times

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Organic electroluminescent devices with saturated red emission were developed using 6,13-diphenylpentacene (DPP) doped into tris(8-hydroxyquinolinato) aluminum III (Alq3). DPP exhibits a narrow emission spectrum giving rise to a saturated red peak, centered around 625 nm, with excellent chromaticity coordinates (x = 0.63 and y = 0.34) in accordance with the Commission Internationale de l’Eclairage. An absolute photoluminescence (PL) quantum yield (ϕPL) of ∼30% was measured for a composite film of 0.55 mol % of DPP doped into Alq3. An electroluminescence (EL) quantum efficiency of 1.3% at 100 A/m2, close to the estimated theoretical limit (1.5%), was measured for an unoptimized device structure that consists of an active emissive layer sandwiched between hole- and electron-transport layers. In addition, the EL quantum efficiency is constant or stable over a wide range of current densities (1–1000 A/m2) or luminance values (1–1000 cd/m2). © 2001 American Institute of Physics.
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85.60.Jb Light-emitting devices
78.60.Fi Electroluminescence
78.66.Qn Polymers; organic compounds
78.55.Kz Solid organic materials

Optical temperature probe

Brett A. Hooper, Yacov Domankevitz, R. Rox Anderson, and Charles Lin

Appl. Phys. Lett. 78, 2381 (2001); http://dx.doi.org/10.1063/1.1364509 (3 pages) | Cited 3 times

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In order to quantify the energy deposition at a dielectric-tissue interface, a simple optical temperature probe to measure the transient temperature rise of the laser-heated layer at this interface is presented. The optical temperature probe (1) is noninvasive, so as not to alter the optical, thermal, and mechanical properties of the sample, (2) has a fast time response (nanoseconds), in order to measure the temperature increase during a short laser pulse, and (3) has high spatial resolution (micrometers), in order to probe only the heated layer. The probe is also capable of detecting ablation at the optic-tissue interface. © 2001 American Institute of Physics.
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07.20.Dt Thermometers
07.60.-j Optical instruments and equipment

Influence of the injection current dependence of gain suppression on the nonlinear dynamics of semiconductor lasers

C. G. Lim, S. Iezekiel, and C. M. Snowden

Appl. Phys. Lett. 78, 2384 (2001); http://dx.doi.org/10.1063/1.1363698 (3 pages) | Cited 5 times

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A detailed numerical analysis of the nonlinear dynamics of a directly modulated 1.55 μm InGaAsP distributed-feedback laser diode (LD) is carried out. Results show that when simulating the nonlinear dynamics of LDs, it is important to account for the gain suppression being dependent on the injection current. Only when this dependency of gain suppression is included in the conventional single-mode rate equations, can excellent agreement between simulated and measured results be achieved. © 2001 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Fc Modulation, tuning, and mode locking
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Adjustable ultraviolet-sensitive detectors based on amorphous silicon

Marko Topič, Helmut Stiebig, Mathias Krause, and Heribert Wagner

Appl. Phys. Lett. 78, 2387 (2001); http://dx.doi.org/10.1063/1.1365948 (3 pages) | Cited 9 times

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Thin-film detectors made of hydrogenated amorphous silicon (a-Si:H) and amorphous silicon carbide (a-SiC:H) with adjustable sensitivity in the ultraviolet (UV) spectrum were developed. Thin PIN diodes deposited on glass substrates in N–I–P layer sequence with a total thickness of down to 33 nm and a semitransparent Ag front contact were fabricated. The optimized diodes with a 10 nm Ag contact exhibit spectral response values above 80 mA/W in the wavelength range from 295 to 395 nm with a maximum of 91 mA/W at 320 nm. For longer wavelengths, the spectral response drops by 50% at 450 nm. Increasing the thickness of the Ag front contact leads to a narrowing of the spectral response at around 320 nm, which allows the adjustment from a broad UV to a selective UV–B-sensitive detector. © 2001 American Institute of Physics.
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42.79.Pw Imaging detectors and sensors
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Dw Photodiodes; phototransistors; photoresistors

Effect of indium content on the normal-incident photoresponse of InGaAs/GaAs quantum-well infrared photodetectors

J. Hernando, J. L. Sánchez-Rojas, A. Guzmán, E. Muñoz, J. M. G. Tijero, D. González, G. Aragón, and R. García

Appl. Phys. Lett. 78, 2390 (2001); http://dx.doi.org/10.1063/1.1365951 (3 pages) | Cited 2 times

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Longwavelength InGaAs/GaAs quantum-well infrared photodetectors with indium contents ranging from 25% to 40% have been grown and characterized. Material quality has been assessed by photoluminescence and transmission electron microscopy. Intersubband photocurrent, excited by polarized (TE or TM) infrared light, has been analyzed in order to determine the responsivity for normal-incident radiation. It is found that the TE to TM responsivity ratio is lower than 10% in all the samples studied. By changing the indium content from 25% to 40%, the increase in the TE to TM photoresponse ratio is as low as 3%. Our results are opposite to previous reports of experimental observation of significant TE-polarized light absorption. However, the low efficiency for normal-incident radiation agrees with various theoretical predictions. © 2001 American Institute of Physics.
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85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
85.60.Gz Photodetectors (including infrared and CCD detectors)
73.50.Pz Photoconduction and photovoltaic effects
78.67.De Quantum wells
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Ion-beam-induced deoxyribose nucleic acid transfer

S. Anuntalabhochai, R. Chandej, B. Phanchaisri, L. D. Yu, T. Vilaithong, and I. G. Brown

Appl. Phys. Lett. 78, 2393 (2001); http://dx.doi.org/10.1063/1.1362338 (3 pages) | Cited 20 times

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We report our observations of the interaction of energetic ions with bacterial cells, inducing direct deoxyribose nucleic acid (DNA) transfer into Escherichia coli (E. coli). Argon- and nitrogen-ion beams were used to bombard the bacteria E. coli in a vacuum with energy of 26 keV and fluence in the range 0.5–4×1015 ions/cm2. Three DNA plasmids, pGEM2, pGEM-T easy, and pGFP, carrying different marker genes, were subsequently transferred (separately) into the appropriately ion-bombarded bacteria and successfully expressed. The results of this study indicate that ion beams with an energy such that the ion range is approximately equal to the cell envelope thickness, at a certain range of fluence, are able to generate pathways for macromolecule transfer through the envelope without irreversible damage. © 2001 American Institute of Physics.
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87.53.-j Effects of ionizing radiation on biological systems
87.14.G- Nucleic acids
87.15.M- Spectra of biomolecules
87.16.-b Subcellular structure and processes

Ordered stretching of single molecules of deoxyribose nucleic acid between microfabricated polystyrene lines

D. C. G. Klein, L. Gurevich, J. W. Janssen, L. P. Kouwenhoven, J. D. Carbeck, and L. L. Sohn

Appl. Phys. Lett. 78, 2396 (2001); http://dx.doi.org/10.1063/1.1365099 (3 pages) | Cited 14 times

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A technique for creating arrays of parallel, stretched single molecules of deoxyribose nucleic acid (DNA) on an arbitrary substrate for high-resolution scanning-probe imaging is discussed. The technique consists of lithographically patterning polystyrene lines on a substrate which then provide attachment sites for the ends of individual DNA molecules. Molecular combing is performed to stretch DNA from one polystyrene line to the other. Scanning-tunneling and atomic-force microscope images of single molecules of bacteriophage-lambda DNA are shown to demonstrate the advantages of this technique. Several applications, from high-resolution genomics to molecular electronics, are discussed. © 2001 American Institute of Physics.
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87.14.G- Nucleic acids
07.79.-v Scanning probe microscopes and components
87.64.Dz Scanning tunneling and atomic force microscopy
87.85.Va Micromachining
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Direct measurement of the attenuation of capillary waves by laser interferometry: Noncontact determination of viscosity

F. Behroozi, B. Lambert, and B. Buhrow

Appl. Phys. Lett. 78, 2399 (2001); http://dx.doi.org/10.1063/1.1365413 (3 pages) | Cited 7 times

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The determination of viscosity from the damping of capillary waves has been of great interest, as it affords the possibility of measuring viscosity without contact with the fluid. Here we describe a noncontact method for precision measurement of the amplitude of capillary waves on fluids. The technique utilizes a miniature laser interferometer to map the wave profile with a resolution of about 10 nm. We use this technique to obtain the dispersion and attenuation of capillary waves on water as a test case. Furthermore, the attenuation data is used to obtain the viscosity of water as a function of temperature. © 2001 American Institute of Physics.
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47.35.-i Hydrodynamic waves
66.20.-d Viscosity of liquids; diffusive momentum transport
47.80.-v Instrumentation and measurement methods in fluid dynamics
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy

Mechanisms for O2 dissociation during pulsed-laser ablation and deposition

A. Camposeo, F. Cervelli, F. Fuso, M. Allegrini, and E. Arimondo

Appl. Phys. Lett. 78, 2402 (2001); http://dx.doi.org/10.1063/1.1366363 (3 pages) | Cited 15 times

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We investigate different dissociation mechanisms for O2 gas during pulsed-laser ablation and deposition. Mesaurements are carried out by using an in situ diagnostics based on absorption spectroscopy of oxygen gas, with space- and time-resolved capabilities, during laser ablation of a metal alloy target in the presence of an oxygen environment. Data, analyzed as a function of ablation parameters, indicate that two different mechanisms, involving electron collisions and formation of a high-density, high-temperature shock layer, play an important role in producing atomic oxygen which can subsequently react with the ablated species. © 2001 American Institute of Physics.
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79.20.Ds Laser-beam impact phenomena
82.50.Hp Processes caused by visible and UV light
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
33.80.Gj Diffuse spectra; predissociation, photodissociation
34.80.Ht Dissociation and dissociative attachment
81.15.Fg Pulsed laser ablation deposition
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
81.65.-b Surface treatments
07.57.-c Infrared, submillimeter wave, microwave and radiowave instruments and equipment
07.60.-j Optical instruments and equipment
82.40.Fp Shock wave initiated reactions, high-pressure chemistry
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