SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Kuznetsov A. Yu.) "

Sökning: WFRF:(Kuznetsov A. Yu.)

  • Resultat 1-43 av 43
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • 2017
  • swepub:Mat__t
  •  
2.
  • Abazov, V. M., et al. (författare)
  • The upgraded DO detector
  • 2006
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
  • Tidskriftsartikel (refereegranskat)abstract
    • The DO experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid -argon calorimeters and central muon detector, remaining from Run 1, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DO.
  •  
3.
  • Akhunzyanov, R., et al. (författare)
  • Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section
  • 2019
  • Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 793, s. 188-194
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on the first measurement of exclusive single-photon muoproduction on the proton by COMPASS using 160 GeV/c polarised mu(+) and mu(-) beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average of the measured mu(+) and mu(-) cross sections for deeply virtual Compton scattering on the squared four-momentum transfer t from the initial to the final proton. The slope B of the t-dependence is fitted with a single exponential function, which yields B = (4.3 +/- 0.6(stat) (+0.1)(-0.3)vertical bar(sys)) (GeV/c)(-2). This result can be converted into a transverse extension of partons in the proton,root(r(perpendicular to)(2)) = (0.58 +/- 0.04(stat) (+0.01)(-0.02)vertical bar(sys) +/- 0.04(model)) fm. For this measurement, the average virtuality of the photon mediating the interaction is < Q(2)> = 1.8 (GeV/c)(2) and the average value of the Bjorken variable is < X-Bj > = 0.056.
  •  
4.
  • Jackura, A., et al. (författare)
  • New analysis of eta pi tensor resonances measured at the COMPASS experiment
  • 2018
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 779, s. 464-472
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a new amplitude analysis of the eta pi D-wave in the reaction pi(-) p -> eta pi(-) p measured by COMPASS. Employing an analytical model based on the principles of the relativistic S-matrix, we find two resonances that can be identified with the a(2)(1320) and the excited a(2)(1700), and perform a comprehensive analysis of their pole positions. For the mass and width of the a(2) we find M = (1307 +/- 1 6) MeV and Gamma=(112 +/- 1 +/- 8) MeV, and for the excited state a(2)' we obtain M = (1720 +/- 10 +/- 60) MeV and Gamma = (280 +/- 10 +/- 70) MeV, respectively.
  •  
5.
  • Aghasyan, M., et al. (författare)
  • Light isovector resonances in pi(-) p -> pi(-) pi(-) pi(+)p at 190 GeV/c
  • 2018
  • Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 98:9
  • Tidskriftsartikel (refereegranskat)abstract
    • We have performed the most comprehensive resonance-model fit of pi(-)pi(-)pi(+) states using the results of our previously published partial-wave analysis (PWA) of a large data set of diffractive-dissociation events from the reaction pi(-) + p -> pi(-)pi(-)pi(+) +p(recoil) with a 190 GeV/c pion beam. The PWA results, which were obtained in 100 bins of three-pion mass, 0.5 < m(3 pi) < 2.5 GeV/c(2), and simultaneously in 11 bins of the reduced four-momentum transfer squared, 0.1 < t'< 1.0 (GeV/c)(2), are subjected to a resonance-model fit using Breit-Wigner amplitudes to simultaneously describe a subset of 14 selected waves using 11 isovector light-meson states with J(PC) = 0(-+), 1(++), 2(++), 2(-+), 4(++), and spin-exotic 1(-+) quantum numbers. The model contains the well-known resonances pi(1800), a(1)(1260), a(2)(1320), pi(2)(1670), pi(2)(1880), and a(4) (2040). In addition, it includes the disputed pi(1)(1600), the excited states a(1)(1640), a2(1700), and pi(2) (2005), as well as the resonancelike a(1)(1420). We measure the resonance parameters mass and width of these objects by combining the information from the PWA results obtained in the 11 t' bins. We extract the relative branching fractions of the rho(770)pi and f(2)(1270)pi decays of a(2)(1320) and a(4)(2040), where the former one is measured for the first time. In a novel approach, we extract the t' dependence of the intensity of the resonances and of their phases. The t' dependence of the intensities of most resonances differs distinctly from the t' dependence of the nonresonant components. For the first time, we determine the t' dependence of the phases of the production amplitudes and confirm that the production mechanism of the Pomeron exchange is common to all resonances. We have performed extensive systematic studies on the model dependence and correlations of the measured physical parameters.
  •  
6.
  • Aghasyan, M., et al. (författare)
  • Longitudinal double-spin asymmetry A(1)(p) and spin-dependent structure function g(1)(p) of the proton at small values of x and Q(2)
  • 2018
  • Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 781, s. 464-472
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a precise measurement of the proton longitudinal double-spin asymmetry A(1)(p) and the proton spin-dependent structure function g(1)(P) at photon virtualities 0.006 (GeV/c)(2) < Q(2) < 1 (GeV/c)(2) in the Bjorken x range of 4 x 10(-5) < x < 4 x 10(-2). The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160 GeV and 200 GeV. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of x, the measured values of A(1)(p) and g(1)(P) are found to be positive. It is for the first time that spin effects are found at such low values of x.
  •  
7.
  • Aghasyan, M., et al. (författare)
  • Search for muoproduction of X(3872) at COMPASS and indication of a new state (X)over-tilde(3872)
  • 2018
  • Ingår i: Physics Letters B. - : ELSEVIER SCIENCE BV. - 0370-2693 .- 1873-2445. ; 783, s. 334-340
  • Tidskriftsartikel (refereegranskat)abstract
    • We have searched for exclusive production of exotic charmonia in the reaction mu N+ -> mu(+)(J/psi pi(+)pi(-))pi N-+/-' using COMPASS data collected with incoming muons of 160 GeV/c and 200 GeV/c momentum. In the J/psi pi(vertical bar)pi mass distribution we observe a signal with a statistical significance of 4.1 sigma. Its mass and width are consistent with those of the X(3872). The shape of the pi(+)pi(-) mass distribution from the observed decay into J/psi pi(+)pi(-) shows disagreement with previous observations for X(3872). The observed signal may be interpreted as a possible evidence of a new charmonium state. It could be associated with a neutral partner of X(3872) with C=-1 predicted by a tetraquark model. The product of cross section and branching fraction of the decay of the observed state into J/psi pi(+)pi(-) is determined to be 71 +/- 28(stat)+/- 39(syst) pb.
  •  
8.
  • Aghasyan, M., et al. (författare)
  • Transverse-momentum-dependent multiplicities of charged hadrons in muon-deuteron deep inelastic scattering
  • 2018
  • Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:3
  • Tidskriftsartikel (refereegranskat)abstract
    • A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality Q(2) > 1 (GeV/c)(2), invariant mass of the hadronic system W > 5 (GeV/c)(2), Bjorken scaling variable in the range 0.003 < x < 0.4, fraction of the virtual photon energy carried by the hadron in the range 0.2 < z < 0.8, and square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/c)(2) < P-hT(2) < 3 (GeV/c)(2). The multiplicities are presented as a function of P-hT(2) in three-dimensional bins of x, Q(2), z and compared to previous semi-inclusive measurements. We explore the small-P-hT(2) region, i.e. P-hT(2) < 1 (GeV/c)(2), where hadron transverse momenta are expected to arise from nonperturbative effects, and also the domain of larger P-hT(2), where contributions from higher-order perturbative QCD are expected to dominate. The multiplicities are fitted using a single-exponential function at small P-hT(2) to study the dependence of the average transverse momentum < P-hT(2)> on x, Q(2) and z. The power-law behavior of the multiplicities at large P-hT(2) is investigated using various functional forms. The fits describe the data reasonably well over the full measured range.
  •  
9.
  • Abdellaoui, G., et al. (författare)
  • Meteor studies in the framework of the JEM-EUSO program
  • 2017
  • Ingår i: Planetary and Space Science. - : Elsevier. - 0032-0633 .- 1873-5088. ; 143, s. 245-255
  • Tidskriftsartikel (refereegranskat)abstract
    • We summarize the state of the art of a program of UV observations from space of meteor phenomena, a secondary objective of the JEM-EUSO international collaboration. Our preliminary analysis indicates that JEM-EUSO, taking advantage of its large FOV and good sensitivity, should be able to detect meteors down to absolute magnitude close to 7. This means that JEM-EUSO should be able to record a statistically significant flux of meteors, including both sporadic ones, and events produced by different meteor streams. Being unaffected by adverse weather conditions, JEM-EUSO can also be a very important facility for the detection of bright meteors and fireballs, as these events can be detected even in conditions of very high sky background. In the case of bright events, moreover, exhibiting some persistence of the meteor train, preliminary simulations show that it should be possible to exploit the motion of the ISS itself and derive at least a rough 3D reconstruction of the meteor trajectory. Moreover, the observing strategy developed to detect meteors may also be applied to the detection of nuclearites, exotic particles whose existence has been suggested by some theoretical investigations. Nuclearites are expected to move at higher velocities than meteoroids, and to exhibit a wider range of possible trajectories, including particles moving upward after crossing the Earth. Some pilot studies, including the approved Mini-EUSO mission, a precursor of JEM-EUSO, are currently operational or in preparation. We are doing simulations to assess the performance of Mini-EUSO for meteor studies, while a few meteor events have been already detected using the ground-based facility EUSO-TA.
  •  
10.
  • Abdellaoui, G., et al. (författare)
  • First observations of speed of light tracks by a fluorescence detector looking down on the atmosphere
  • 2018
  • Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 13
  • Tidskriftsartikel (refereegranskat)abstract
    • EUSO-Balloon is a pathfinder mission for the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). It was launched on the moonless night of the 25(th) of August 2014 from Timmins, Canada. The flight ended successfully after maintaining the target altitude of 38 km for five hours. One part of the mission was a 2.5 hour underflight using a helicopter equipped with three UV light sources (LED, xenon flasher and laser) to perform an inflight calibration and examine the detectors capability to measure tracks moving at the speed of light. We describe the helicopter laser system and details of the underflight as well as how the laser tracks were recorded and found in the data. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. Finally, we present a first reconstruction of the direction of the laser tracks relative to the detector.
  •  
11.
  • Akimov, D., et al. (författare)
  • Physics with WASA and PROMICE
  • 1994
  • Ingår i: Physics with GeV-particle beams, Juelich 1994. ; , s. 519-530
  • Konferensbidrag (refereegranskat)
  •  
12.
  • Zubkov, V. G., et al. (författare)
  • Structural, vibrational, electronic, and luminescence properties of the cyclotetravanadates A(2)M(VO3)(4) (A=Na,Ag; M=Ca,Sr)
  • 2008
  • Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 77, s. 174113-
  • Tidskriftsartikel (refereegranskat)abstract
    • The physical properties of the family of cyclotetravanadates A(2)M(VO3)(4), where A=Na,Ag and M=Ca,Sr, have been studied by means of x-ray powder diffraction, neutron diffraction, electron diffraction, infrared, Raman, NMR, photoexcitation and pulse cathode beam excitation, and x-ray photoelectron spectroscopies, and band structure calculations. The differences between the structural, vibrational, luminescence, and electronic properties of the alkali metal-containing [Na2Ca(VO3)(4) and Na2Sr(VO3)(4)] and the d metal-containing cyclotetravanadates [Ag2Ca(VO3)(4) and Ag2Sr(VO3)(4)] are analyzed. Na2Ca(VO3)(4), Ag2Ca(VO3)(4), Na2Sr(VO3)(4), and Ag2Sr(VO3)(4) have tetragonal structures, P4/nbm, with a=10.438 49(6), 10.445 24(5), 10.634 49(4), and 10.625 74(6), and c=4.938 73(5), 4.968 45(5), 4.962 05(4), and 4.979 30(4) angstrom, respectively. The main structural feature of A(2)M(VO3)(4) is the tetracyclic [V4O12] units. The hybridized O 2p-V 3d states of the tetracyclic [V4O12] units have a dominant influence on the electronic structure of these compounds. The compounds are semiconducting with a local density approximation band gap increasing, from 1.85 eV for Ag2Ca(VO3)(4) to 3.02 eV for Na2Ca(VO3)(4). The prospects of these compounds as advanced materials for detectors of photon and corpuscular radiation as well as for color correction of light emission sources such as lamp and light emitting diode sources are discussed.
  •  
13.
  • Azarov, A. Yu., et al. (författare)
  • Structural damage in ZnO bombarded by heavy ions
  • 2010
  • Ingår i: Vacuum. - : Elsevier BV. - 0042-207X .- 1879-2715. ; 84:8, s. 1058-1061
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of implantation parameters on damage build-up in ZnO bombarded with Bi and Er ions is studied by Rutherford backscattering/channelling spectrometry. The results show that the damage accumulation behaviour in ZnO is different dramatically from that in other semiconductors. In particular, a variation of implantation parameters, such as collision cascade density, sample temperature and ion flux, has only a minor influence on the damage accumulation in the crystal bulk for the case of such heavy ions. Moreover, an intermediate damage peak, between the surface and bulk defect peaks, is observed for all the irradiation conditions studied. The cascade density affects the behaviour of this intermediate peak with increasing ion dose.
  •  
14.
  •  
15.
  • Azarov, A. Yu, et al. (författare)
  • Annealing of ion implanted CdZnO
  • 2012
  • Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 45:23, s. 235304-
  • Tidskriftsartikel (refereegranskat)abstract
    • We have studied the effect of the Cd content on the recovery of ion-induced damage in wurtzite CdxZn1-xO (x <= 0.05) films and compared with that in pure wurtzite ZnO and rock-salt CdO.200 keV Au+ and 55 keV Ar+ ion implants were performed at room temperature in the dose range of 5 x 1014-6.5 x 1015 cm-2. Rutherford backscattering/channelling spectrometry was used to characterize the damage evolution in the course of annealing (600-900 degrees C in air). A complex defect annealing behaviour is revealed in CdZnO as a function of annealing temperature, Cd content and ion dose. In particular, defects in the low dose implanted CdZnO films can be effectively removed at 800 degrees C, while the high dose implantation results in the formation of defects stable at least up to 900 degrees C. Moreover, annealing of the CdZnO films is accompanied by Cd loss at the surface for temperatures exceeding 800 degrees C. In contrast, CdO exhibits a typical damage accumulation behaviour for metals and semiconductors with high degree of ionicity, resulting in saturation and extended defect formation at high ion doses. These extended defects in pure ZnO and CdO, formed either directly during implantation or by reconstruction during post-implant annealing, are substantially more stable compared with small defects which can be efficiently removed at 700 degrees C and 600 degrees C for ZnO and CdO, respectively.
  •  
16.
  • Azarov, A. Yu., et al. (författare)
  • Damage accumulation and annealing behavior in high fluence implanted MgZnO
  • 2012
  • Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 272, s. 426-429
  • Tidskriftsartikel (refereegranskat)abstract
    • Molecular beam epitaxy grown MgxZn1-xO (x <= 0.3) layers were implanted at room temperature with 150 keV Er-166(+) ions in a fluence range of 5 x 10(15-)3 x 10(16) cm(-2). Evolution of ion-induced damage and structural changes were studied by a combination of Rutherford backscattering spectrometry, nuclear reaction analysis and time-of-flight elastic recoil detection analysis. Results show that damage production enhances in both Zn- and O-sublattices with increasing the Mg content in the MgZnO. However, MgZnO as well as pure ZnO exhibits a high degree of dynamic annealing and MgZnO can not be amorphized even at the highest ion fluence used. Annealing of heavily damaged ZnO leads to a strong surface erosion and thinning of the film. Increasing the Mg content suppresses the surface evaporation in high fluence implanted MgZnO but leads to a strong surface decomposition accompanied with a Mg-rich surface layer formation during post-implantation annealing.
  •  
17.
  • Azarov, A. Yu., et al. (författare)
  • Effect of composition on damage accumulation in ternary ZnO-based oxides implanted with heavy ions
  • 2010
  • Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 108:3, s. 033509-
  • Tidskriftsartikel (refereegranskat)abstract
    • Thin films of wurtzite MgxZn1-xO (x <= 0.3) grown by molecular beam epitaxy and wurtzite CdxZn1-xO (x <= 0.05) grown by metal organic chemical vapor deposition were implanted at room temperature with 150 keV Er+ ions and 200 keV Au+ ions in a wide dose range. Damage accumulation was studied by Rutherford backscattering/channeling spectrometry. Results show that the film composition affects the damage accumulation behavior in both MgZnO and CdZnO dramatically. In particular, increasing the Mg content in MgZnO results in enhanced damage accumulation in the region between the bulk and surface damage peaks characteristically distinguished in the pure ZnO. However, the overall damage accumulation in MgZnO layers, as well as in pure ZnO, exhibits saturation with increasing ion dose and MgZnO cannot be amorphized even at the highest ion dose used (3 X 10(16) Er/cm(2)). Increasing the Cd content in CdZnO affects the saturation stage of the damage accumulation and leads to an enhancement of damage production in both Cd and Zn sublattices. (C) 2010 American Institute of Physics. [doi:10.1063/1.3467532]
  •  
18.
  • Azarov, A. Yu, et al. (författare)
  • Effect of implanted species on thermal evolution of ion-induced defects in ZnO
  • 2014
  • Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 115:7, s. 073512-
  • Tidskriftsartikel (refereegranskat)abstract
    • Implanted atoms can affect the evolution of ion-induced defects in radiation hard materials exhibiting a high dynamic annealing and these processes are poorly understood. Here, we study the thermal evolution of structural defects in wurtzite ZnO samples implanted at room temperature with a wide range of ion species (from B-11 to Bi-209) to ion doses up to 2 x 10(16) cm(-2). The structural disorder was characterized by a combination of Rutherford backscattering spectrometry, nuclear reaction analysis, and transmission electron microscopy, while secondary ion mass spectrometry was used to monitor the behavior of both the implanted elements and residual impurities, such as Li. The results show that the damage formation and its thermal evolution strongly depend on the ion species. In particular, for F implanted samples, a strong out-diffusion of the implanted ions results in an efficient crystal recovery already at 600 degrees C, while co-implantation with B (via BF2) ions suppresses both the F out-diffusion and the lattice recovery at such low temperatures. The damage produced by heavy ions (such as Cd, Au, and Bi) exhibits a two-stage annealing behavior where efficient removal of point defects and small defect clusters occurs at temperatures similar to 500 degrees C, while the second stage is characterized by a gradual and partial annealing of extended defects. These defects can persist even after treatment at 900 degrees C. In contrast, the defects produced by light and medium mass ions (O, B, and Zn) exhibit a more gradual annealing with increasing temperature without distinct stages. In addition, effects of the implanted species may lead to a nontrivial defect evolution during the annealing, with N, Ag, and Er as prime examples. In general, the obtained results are interpreted in terms of formation of different dopant-defect complexes and their thermal stability.
  •  
19.
  • Azarov, A. Yu., et al. (författare)
  • Thermally induced surface instability in ion-implanted Mg(x)Zn(1-x)O films
  • 2011
  • Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 84:1, s. 014114-
  • Tidskriftsartikel (refereegranskat)abstract
    • Thermal stability of originally single crystalline wurtzite Mg(x)Zn(1-x)O (x <= 0.3) films implanted at room temperature with (166)Er ions is studied by a combination of Rutherford backscattering spectrometry, time-of-flight elastic recoil detection analysis, x-ray diffraction analysis, and atomic force microscopy. The MgZnO films exhibit a complex behavior during postimplantation annealing associated with compositional changes and surface erosion in addition to Er accumulation at the surface. The importance of these processes depends on the Mg content, annealing temperature, and amount of implantation damage. Specifically, increases in the Mg content as well as the implantation damage enhance the compositional changes in the near-surface region and give rise to altered stoichiometry and Mg-enriched phase separation. In its turn, the rate of surface erosion in MgZnO under the thermal treatment depends on temperature, MgZnO composition, and the amount of implantation damage nontrivially, which is attributed to the compositional changes in the near-surface region assisted by the implantation damage.
  •  
20.
  • Gorbatov, O. I., et al. (författare)
  • Role of Magnetism in the Formation of a Short-Range Order in Iron-Silicon Alloys
  • 2011
  • Ingår i: Journal of Experimental and Theoretical Physics. - 1063-7761 .- 1090-6509. ; 112:5, s. 848-859
  • Tidskriftsartikel (refereegranskat)abstract
    • The formation of a short-range order in soft magnetic Fe-Si alloys depending on the annealing temperature has been investigated theoretically and experimentally. The B2-type short-range order has been observed in samples quenched from temperatures T > T(C) (where T(C) is the Curie temperature) with the content c(Si) close to the boundary of the two-phase region. Annealing at temperatures T < T(C) for the content c(Si) >= 0.08 leads to an increase in the fraction of regions with the D0(3)-type short-range order. The mechanism of the formation of the short-range order in Fe-Si solid solutions has been analyzed by the Monte Carlo simulation with the ab initio calculated interatomic interaction parameters. It has been shown that the energy of the effective Si-Si interaction in bcc iron strongly depends on the magnetic state of the matrix. As a result, the B2-type short-range order is formed at T > T(C) and is fixed at quenching, whereas the D0(3)-type short-range order is equilibrium in the ferromagnetic state. The results reveal the decisive role of magnetism in the formation of the short-range order in Fe-Si alloys and allow the explanation of the observed structural features of the alloys depending on the composition and temperature.
  •  
21.
  • Liang, H. L., et al. (författare)
  • Growth of single-phase Mg0.3Zn0.7O films suitable for solar-blind optical devices on RS-MgO substrates
  • 2012
  • Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 520:6, s. 1705-1708
  • Tidskriftsartikel (refereegranskat)abstract
    • Single-phase rock-salt Mg0.3Zn0.7O film was fabricated on MgO (100) substrate by radio-frequency plasma assisted molecular beam epitaxy. A smooth surface was observed by in-situ reflection high-energy electron diffraction and ex-situ atomic force microscopy. X-ray diffraction characterization demonstrated a high-quality single-phase structure with highly (200) orientation and cube-on-cube epitaxial relationship. Zn fraction in the single-phase rock-salt Mg0.3Zn0.7O film was determined by Rutherford backscattering spectrometry. Optical property of the film was investigated by reflectance spectroscopy, which indicated a solar-blind band gap of 255.5 nm. The reason why Zn solubility limit is greatly enhanced in non-polar (100) film compared with (111) polar epilayer is tentatively discussed in this work, suggesting MgO (100) is more suitable for the synthesis of single-phase rock-salt MgZnO with high Zn content towards solar-blind opto-device applications.
  •  
22.
  • Liang, H. L., et al. (författare)
  • High Zn content single-phase RS-MgZnO suitable for solar-blind frequency applications
  • 2010
  • Ingår i: 2010 Wide Bandgap Cubic Semiconductors. - : American Institute of Physics (AIP). - 9780735408470 ; , s. 185-190
  • Konferensbidrag (refereegranskat)abstract
    • Single-phase rock-salt MgZnO films with high Zn content were successfully fabricated on the templates of MgO (111)/α-sapphire (0001) by radio-frequency plasma assisted molecular beam epitaxy. The influence of growth temperature on epitaxy of MgZnO alloy films was investigated by the combined studies of crystal structures, compositions, and optical properties. It is found that the incorporation of Zn atoms into the rock-salt MgZnO films is greatly enhanced at low temperature, confirmed by in-situ reflection high-energy electron diffraction observations and ex-situ X-ray diffraction characterization. Zn fraction in the single-phase rock-salt Mg 0.53Zn0.47O film was determined by Rutherford backscattering spectrometry. Optical properties of the films were investigated by transmittance spectroscopy and reflectance spectroscopy, both of which demonstrate the solar-blind band gap and its dependence on Zn content.
  •  
23.
  • Severo, J. H. F., et al. (författare)
  • Error analysis in the electron temperature measurements in TCABR
  • 2012
  • Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 370:1, s. 012045-
  • Tidskriftsartikel (refereegranskat)abstract
    • An analytical method is proposed to evaluate the experimental uncertainty in the electron temperature measurements in the TCABR tokamak. Solving the integral equation resulting from the convolution of two functions, one representing, the scattered light and the other the spectral apparatus function, i.e., the polychromator, an analytical expression for the electron temperature is obtained, from which the uncertainty in the measured value is readily evaluated. The results show that the major contribution to the error comes from the noise in the signal; the uncertainties in the filters parameters do not contribute significantly to the total error.
  •  
24.
  • Christensen, J. S., et al. (författare)
  • Phosphorus diffusion in the presence of threading dislocations in strain relaxed SiGe films
  • 2006
  • Ingår i: Materials Science in Semiconductor Processing. - : Elsevier BV. - 1369-8001 .- 1873-4081. ; 9:4-5, s. 650-654
  • Tidskriftsartikel (refereegranskat)abstract
    • We have studied phosphorus diffusion in strain relaxed Si1-xGex films (x = 0.1 and 0.2) by secondary ion mass spectrometry (SIMS). The relaxed films were grown with low-pressure chemical vapor deposition (LPCVD) on a Si substrate followed by a graded SiGe layer. Two sets of samples were prepared under different growth conditions, and by transmission electron microscopy (TEM) it was shown that these conditions resulted in one set of samples containing a high density of threading dislocations in the relaxed films, and one set with a low dislocation density. The SIMS profiles of the phosphorus distributions in the samples, after annealing in N-2-ambient in the temperature range of 700-950 degrees C, show that the phosphorus diffusion is significantly faster in the films with the high dislocation density. Furthermore, the data suggests that the fast diffusion is due to a higher mobility of the diffusing complex rather than an increase in the point defect concentration mediating the diffusion, a result which indicates that the threading dislocations may act as channels for the rapid dopant diffusion in SiGe.
  •  
25.
  • García-Fernández, J., et al. (författare)
  • In situ atomic-resolution study of transformations in double polymorph ?/ß-Ga 2 O 3 structures
  • 2024
  • Ingår i: Materials Advances. - 2633-5409. ; 5:9, s. 3824-3831
  • Tidskriftsartikel (refereegranskat)abstract
    • Disorder-induced formation of metastable Ga2O3 polymorphs as well as the recovery of the stable state upon annealing attract attention because of the fundamental novelty and rapidly increasing interest in the use of Ga2O3 in practical applications. In this study, double polymorph ?/ß-Ga2O3 structures fabricated by the radiation-induced disorder approach were used as a starting point for systematic in situ annealing electron microscopy experiments. We show that, under the conditions of the TEM in situ annealing, double ?/ß-Ga2O3 polymorph structures remained stable up to 300 °C, when onsets of the ?-to-ß transformation become traceable, leading to a prominent ?- and ß-mixture already at 500 °C. Interestingly, the recrystallization of the ß-Ga2O3 occurs throughout the whole ?-film and the preferential alignments at the newly emerging ?/ß-interfaces are different from that of the initial ?/ß-interface formed as a result of the disorder-induced ordering. The alignments of the two polymorphs are maintained as a function of temperature - with a reduction in the volumetric ratio of ?-domains for increasing annealing temperature. Finally, at 1100 °C, ?-Ga2O3 fully transforms into ß-Ga2O3, without dominating crystallographic relationships or preferred orientations, indicating that energy barriers are not any longer implied limiting factors, because of a sufficiently high thermal energy supply. Thus, these TEM in situ measurements enable a new level of accuracy for assessing polymorphic transformations in Ga2O3
  •  
26.
  • Karkin, I. N., et al. (författare)
  • Segregation of Mg to generic tilt grain boundaries in Al : Monte Carlo modeling
  • 2015
  • Ingår i: Materials Physics and Mechanics. - : Institute of Problems of Mechanical Engineering. - 1605-2730 .- 1605-8119. ; 24:3, s. 201-210
  • Tidskriftsartikel (refereegranskat)abstract
    • The formation of equilibrium segregations at tilt grain boundaries of several different types in Al-Mg alloys has been investigated in the framework of a combined approach, which includes molecular dynamics simulation and thermodynamic Monte Carlo modeling. The concentration profile of Mg distribution in GB vicinity was calculated in dependence on the alloy concentration and temperature. We found that width of segregation on generic GB determined by feature of their structure and is match bigger in comparison with special lowenergy GB. It is shown that segregation formation is control not only energy gain due to moving solute on GB but also interaction between solute atoms; as results, maximal enrichment of GB is not exceed 25 at.%. Possible origins of the formation of extended segregation on GB in materials subjected by severe plastic deformation have been discussed.
  •  
27.
  • Karkina, L. E., et al. (författare)
  • Solute-grain boundary interaction and segregation formation in Al : First principles calculations and molecular dynamics modeling
  • 2016
  • Ingår i: Computational materials science. - : Elsevier. - 0927-0256 .- 1879-0801. ; 112, s. 18-26
  • Tidskriftsartikel (refereegranskat)abstract
    • The interaction between solute atoms (Mg, Si, Ti) and grain boundaries (GBs) of different types in Al are investigated using two approaches: first principles total energy calculations and large scale atomistic simulations. We have found that both deformation (size effect) and electronic (charge transfer) mechanisms play an important role in solute-GB interaction. The deformation and electronic contributions to GB segregation energy for the considered solutes have been analyzed in dependence on the impurity and the GB type. Mg and Si atoms are calculated to segregate to GBs, while Ti atoms to repel from, GBs in Al. For the case of a symmetric special-type GB the interaction is found to be short-ranged. For a general-type GB the range of GB-solute interaction is found to be considerably longer. A method to estimate the segregation capacity of a GB has been proposed, which takes into account the solute-solute interactions, and shown to be able to correctly describe the GB enrichment in alloying elements. The features of the segregation formation in fine-grained materials produced by severe plastic deformation are discussed.
  •  
28.
  • Kowalczyk, P., et al. (författare)
  • Two-parameter discontinuity-induced bifurcations of limit cycles : Classification and open problems
  • 2006
  • Ingår i: International Journal of Bifurcation and Chaos in Applied Sciences and Engineering. - 0218-1274. ; 16:3, s. 601-629
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper proposes a strategy for the classification of codimension-two discontinuity-induced bifurcations of limit cycles in piecewise smooth systems of ordinary differential equations. Such nonsmooth transitions (also known as C-bifurcations) occur when the cycle interacts with a discontinuity boundary of phase space in a nongeneric way, such as grazing contact. Several such codimension-one events have recently been identified, causing for example, period-adding or sudden onset of chaos. Here, the focus is on codimension-two grazings that are local in the sense that the dynamics can be fully described by an appropriate Poincare map from a neighborhood of the grazing point (or points) of the critical cycle to itself. It is proposed that codimension-two grazing bifurcations can be divided into three distinct types: either the grazing point is degenerate, or the grazing cycle is itself degenerate (e.g. nonhyperbolic) or we have the simultaneous occurrence of two grazing events. A careful distinction is drawn between their occurrence in systems with discontinuous states, discontinuous vector fields, or that with discontinuity in some derivative of the vector field. Examples of each kind of bifurcation are presented, mostly derived from mechanical applications. For each example, where possible, principal bifurcation curves characteristic to the codimension-two scenario are presented and general features of the dynamics discussed. Many avenues for future research are opened.
  •  
29.
  • Olsen, V. S., et al. (författare)
  • Evidence of defect band mechanism responsible for band gap evolution in (ZnO)(1-x)(GaN)(x) alloys
  • 2019
  • Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 100:16
  • Tidskriftsartikel (refereegranskat)abstract
    • It is known that (ZnO)(1-x)(GaN)(x) alloys demonstrate remarkable energy band bowing, making the material absorb in the visible range, in spite of the binary components being classical wide band gap semiconductors. However, the origin of this bowing is not settled; two major mechanisms are under debate: Influence of the orbital repulsion and/or formation of a defect band. In the present work, we applied a combination of the absorption and emission measurements on the samples exhibiting an outstanding nanoscale level of (ZnO)(1-x)(GaN)(x) homogeneity as monitored by the high resolution electron microscopy equipped with the energy dispersive x-ray analysis and the electron energy loss spectroscopy; moreover the experimental data were set in the context of the computational analysis of the alloys employing density functional theory and quasiparticle GW approximation. A prominent discrepancy in the band gap values as deduced from the absorption and emission experiments was observed systematically for the alloys with different compositions and interpreted as evidence for the absorption gap shrinking due to the defect band formation. Computational data support the argument, revealing only minor variations in the bulk of the conduction and valence band structures of the alloys, except for a characteristic "tail" in the vicinity of the valence band maximum. As such, we conclude that the energy gap bowing in (ZnO)(1-x)(GaN)(x) alloys is due to the defect band formation, presumably at the top of the valence band maximum.
  •  
30.
  • Ayedh, H. M., et al. (författare)
  • Carbon vacancy control in p(+)-n silicon carbide diodes for high voltage bipolar applications
  • 2021
  • Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 54:45
  • Tidskriftsartikel (refereegranskat)abstract
    • Controlling the carbon vacancy (V-C) in silicon carbide (SiC) is one of the major remaining bottleneck in manufacturing of high voltage SiC bipolar devices, because V-C provokes recombination levels in the bandgap, offensively reducing the charge carrier lifetime. In literature, prominent V-C evolutions have been measured by capacitance spectroscopy employing Schottky diodes, however the trade-offs occurring in the p(+)-n diodes received much less attention. In the present work, applying similar methodology, we showed that V-C is re-generated to its unacceptably high equilibrium level at similar to 2 x10(13) V-C cm(-3) by 1800 degrees C anneals required for the implanted acceptor activation in the p(+)-n components. Nevertheless, we have also demonstrated that the V-C eliminating by thermodynamic equilibrium anneals at 1500 degrees C employing carbon-cap can be readily integrated into the p(+)-n components fabrication resulting in <= 10(11) V-C cm(-3), potentially paving the way towards the realization of the high voltage SiC bipolar devices.
  •  
31.
  • Azarov, Alexander, et al. (författare)
  • Dopant incorporation in thin strained Si layers implanted with Sb
  • 2010
  • Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 518:9, s. 2474-2477
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of tensile strain on Sb incorporation in Si and its activation during post-implantation annealing has been Studied by a combination of Rutherford backscattering/channeling spectrometry, secondary ion mass spectrometry. X-ray diffraction and 4-point probe measurements Our results show that, for Sb implanted samples a tensile strain has an important role for dopant behavior Particularly, increasing the tensile strain in the Si layer from 0 to 0 8% leads to an enhancement of the fraction of incorporated Sb atoms in substitutional sites already during implantation from similar to 7 to 30% Furthermore, 0 8% strain in antimony doped Si gives similar to 20% reduction in the sheet resistance in comparison to the unstrained sample.
  •  
32.
  • Borseth, T.M., et al. (författare)
  • Identification of oxygen and zinc vacancy optical signals in ZnO
  • 2006
  • Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:26, s. 262112-262115
  • Tidskriftsartikel (refereegranskat)abstract
    • Photoluminescence spectroscopy has been used to study single crystalline ZnO samples systematically annealed in inert, Zn-rich and O-rich atmospheres. A striking correlation is observed between the choice of annealing ambient and the position of the deep band emission (DBE) often detected in ZnO. In particular, annealing in O2 results in a DBE at 2.35±0.05 eV, whereas annealing in the presence of metallic Zn results in DBE at 2.53±0.05 eV. The authors attribute the former band to zinc vacancy (VZn) related defects and the latter to oxygen vacancy (VO) related defects. Additional confirmation for the VO and VZn peak identification comes from the observation that the effect is reversible when O- and Zn-rich annealing conditions are switched. After annealing in the presence of ZnO powder, there is no indication for the VZn- or VO-related bands, but the authors observe a low intensity yellow luminescence band peaking at 2.17 eV, probably related to Li, a common impurity in hydrothermally grown ZnO.
  •  
33.
  • Kilpelainen, S., et al. (författare)
  • Stabilization of Ge-rich defect complexes originating from E centers in Si(1-x)Ge(x):P
  • 2010
  • Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 81:13, s. 132103-
  • Tidskriftsartikel (refereegranskat)abstract
    • Thermal evolution of vacancy complexes was studied in P-doped ([P] = 10(18) cm(-3)) proton irradiated Si(1-x)Ge(x) with Ge contents of 10%, 20%, and 30% in the range of 250-350 degrees C using positron annihilation spectroscopy. The radiation damage recovers in the course of anneals but the final state differs from that in as-grown samples indicating the presence of small Ge clusters in the samples, contrary to the initially random Ge distribution. The activation energy for the annealing process was estimated to be 1.4+/-0.3 eV and attributed to the dissociation energy of the vacancy-phosphorus-germanium (V-P-Ge) complex.
  •  
34.
  •  
35.
  • Kuznetsov, A.Yu., et al. (författare)
  • Diffusion of phosphorus in strained Si/SiGe/Si heterostructures
  • 1999
  • Ingår i: Materials Research Society Symposium - Proceedings. - San Francisco, CA, USA. ; 568:Warrendale, PA, United States, s. 271-276
  • Tidskriftsartikel (refereegranskat)abstract
    • Phosphorus diffusion in a biaxially compressed Si0.87Ge0.13 film has been investigated in the temperature range of 810-900 °C. A significant enhancement of the P diffusion in the biaxially compressed Si0.87Ge0.13 in comparison with P diffusion in Si is observed. Injection of Si self-interstitials (I) during oxidation of a Si-cap in Si/Si0.87Ge0.13/Si heterostructures is used to characterize the atomic mechanism of P diffusion in Si0.87Ge0.13. It is found that the upper limit of the interstitial fraction of the P diffusion in Si0.87Ge0.13 is 0.87 of that in Si. A comparison between B and P diffusivities in SiGe supports the hypothesis of the pairing-controlled mechanism for the diffusion of B in SiGe.
  •  
36.
  • Liu, Z. L., et al. (författare)
  • Solar-blind 4.55 eV band gap Mg0.55Zn0.45O components fabricated using quasi-homo buffers
  • 2009
  • Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248 .- 1873-5002. ; 311:18, s. 4356-4359
  • Tidskriftsartikel (refereegranskat)abstract
    • A route for synthesizing high Mg content single-phase wurtzite MgZnO films having band gaps in the solar-blind region is demonstrated by employing molecular beam epitaxy on Al2O3 substrates. Importantly, a low Mg content "quasi-homo" buffer, Mg0.17Zn0.83O, was applied to accommodate a host of structural discrepancies and therefore, avoiding phase separation in a high Mg content film, Mg0.55Zn0.45O, as proved by X-ray diffraction. The Mg fraction in the overgrown single-phase epilayer, Mg0.55Zn0.45O, was confirmed by Rutherford backscattering spectrometry.
  •  
37.
  • Neuvonen, P. T., et al. (författare)
  • Transportation of Na and Li in hydrothermally grown ZnO
  • 2010
  • Ingår i: Zinc oxide and related materials 2009. - : Materials Research Society. - 9781605111742 ; , s. 29-34
  • Konferensbidrag (refereegranskat)abstract
    • Secondary ion mass spectrometry has been applied to study the transportation of Na and Li in hydrothermally grown ZnO. A dose of 10 15 cm-2 of Na+ was implanted into ZnO to act as a diffusion source. A clear trap limited diffusion is observed at temperatures above 550 °C. From these profiles, an activation energy for the transport of Na of 7 ∼1.7 eV has been extracted. The prefactor for the diffusion constant and the solid solubility of Na cannot be deduced independently from the present data but their product estimated to be ∼ 3 × 1016 cm-1 s-1. A dissociation energy of ∼2.4 eV is extracted for the trapped Na. The measured Na and Li profiles show that Li and Na compete for the same traps and interact in a way that Li is depleted from Na-rich regions. This is attributed to a lower formation energy of Na-on-zinc-site than that for Li-on-zinc-site defects and the zinc vacancy is considered as a major trap for migrating Na and Li atoms. Consequently, the diffasivity of Li is difficult to extract accurately from the present data, but in its interstitial configuration Li is indeed highly mobile having a diffasivity in excess of 10-11 cm2 s-1 at 500 °C .
  •  
38.
  • Nguyen, Son Tien, 1953-, et al. (författare)
  • Magnetic resonance studies of defects in electron-irradiated ZnO substrates
  • 2007
  • Ingår i: Physica. B, Condensed matter. - : Elsevier BV. - 0921-4526 .- 1873-2135. ; 401-402, s. 507-510
  • Tidskriftsartikel (refereegranskat)abstract
    • Optical detection of magnetic resonance (ODMR) was used to study defects in electron-irradiated ZnO substrates. In addition to the shallow donor and the Zn vacancy, several ODMR centers with an effective electron spin were detected. Among these, the axial LU3 and non-axial LU4 centers are shown to be dominating recombination centers. The annealing behavior of radiation-induced defects was studied and possible defect models are discussed.
  •  
39.
  • Severo, J. H. F., et al. (författare)
  • Investigation of rotation at the plasma edge in TCABR
  • 2015
  • Ingår i: Nuclear Fusion. - : Institute of Physics (IOP). - 0029-5515 .- 1741-4326. ; 55:9
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper summarizes experimental results from recent studies on intrinsic rotation at the plasma edge of the TCABR tokamak. These results were obtained after upgrading the number of channels of the rotation diagnostic to three. The measurements were carried out in the collisional (Pfirsch-Schluter) regime and the rotation profiles of the ions were obtained from the Doppler shifts of the impurity carbon lines, CIII (464.74 nm), and CVI (529.06 nm). Results on the correlation between toroidal rotation at the plasma edge and direction of gas injection are also presented. They indicate that the direction of gas injection has a small effect on rotation; the velocity of the background neutral hydrogen is affected by direct momentum transfer from the injected gas (also hydrogen), while the carbon ions' velocity is affected by inward radial friction force between the injected gas atoms and ions, increasing their velocity in the opposite sense of the plasma current.
  •  
40.
  •  
41.
  • Svensson, B.G., et al. (författare)
  • Ion implantation processing and related effects in SiC
  • 2006
  • Ingår i: Silicon Carbide and Related Materials 2005, Pts 1 and 2. - 9780878494255 ; , s. 781-786
  • Konferensbidrag (refereegranskat)abstract
    • A brief survey is given of some recent progress regarding ion implantation processing and related effects in 4H- and 6H-SiC. Four topics are discussed; an empirical ion range distribution simulator, dynamic defect annealing during implantation, formation of highly p(+)-doped layers, and deactivation of N donors by ion-induced defects.
  •  
42.
  • Vines, L, et al. (författare)
  • Effect spatial defect distribution on the electrical behavior of prominent vacancy points defects in swift-ion implanted Si
  • 2009
  • Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 79:7, s. 075206-
  • Tidskriftsartikel (refereegranskat)abstract
    • Samples of epitaxially grown n-type silicon have been implanted at room   temperature with low doses (10(6)-10(9) cm(-2)) of He, C, Si, and I   ions using energies from 2.75 to 46 MeV. Deep level transient   spectroscopy studies reveal that the generation of divacancy (V-2) and   vacancy-oxygen (VO) pairs has a distinct ion mass dependence.   Especially, the doubly negative charge state of the divacancy,   V-2(=/-), decreases in intensity with increasing ion mass compared to   that of the singly negative charge state of the divacancy, V-2(-/0). In   addition, the measurements show also a decrease in the intensity of the   level assigned to VO compared to that of V-2(-/0) with increasing ion   mass. Carrier capture cross-section measurements demonstrate a   reduction in the electron capture rate with increasing ion mass for all   the three levels V-2(-/0), V-2(=/-), and VO; but a gradual recovery   occurs with annealing. Concurrently, the strength of the V-2(-/0) level   decreases in a wide temperature range starting from below 200 degrees   C, accompanied by an increase in the amplitudes of both the VO and   V-2(=/-) peaks. In order to account for these results a model is   introduced where local carrier compensation is a key feature and where   two modes of V-2 are considered: (1) V-2 centers located in regions   with a high defect density around the ion track (V-2(dense)) and (2)   V-2 centers located in regions with a low defect density (V-2(dilute)).   The V-2(dense) fraction does not give any contribution to the V-2(=/-)   signal due to local carrier compensation, and the amplitude of the   V-2(=/-) level is determined by the V-2(dilute) fraction only. The   spatial distributions of defects generated by single-ion impacts were   simulated by Monte Carlo calculations in the binary collision   approximation, and to distinguish between the regions with V-2(dense)   and V-2(dilute) a threshold for the defect generation rate was   introduced. The model is shown to give good quantitative agreement with   the experimentally observed ion mass dependence for the ratio between   the amplitudes of the V-2(=/-) and V-2(-/0) peaks. In particular, the   threshold value for the defect generation rate remains constant   (similar to 1.2 vacancies/ion/A) irrespective of the type of ion used,   which provides strong evidence for the validity of the model. Annealing   at temperatures above similar to 300 degrees C is found to reduce the   spatial localization of the defects and migration of V-2 occurs with   subsequent trapping by interstitial oxygen atoms and formation of   divacancy-oxygen pairs.
  •  
43.
  • Vines, L, et al. (författare)
  • Formation and annealing behavior of prominent point defects in MeV ion implanted n-type epitaxial Si
  • 2009
  • Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5107 .- 1873-4944. ; 159-160, s. 177-181
  • Tidskriftsartikel (refereegranskat)abstract
    • Samples of epitaxially grown n-type Si have been implanted with low doses (< 1 x 10(9) cm(-1)) of He, C, Si, and I ions using energies from 2.75 to 48 MeV. Deep level transient spectroscopy (DLTS) analysis of the implanted samples reveals a stronger signal for the signature of the singly negative charge state of the divacancy (V-2(-/0)) as compared to that of the doubly negative charge state of the divacancy (V-2(=/-)). Isochronal annealing for 20 min ranging from 150 to 400 degrees C results in a gradual decrease ill the DLTS peak amplitude of the V-2(-/0) signature, accompanied by an increase in the peak amplitudes of both the vacancy oxygen pair (VO) and the V-2(=/-) levels, as well as an increase in the carrier Capture rates for the levels. A model based on local compensation of charge carriers front individual ion tracks is proposed in order to explain the results, involving two fractions of V-2: (1) V-2 centers localized in regions with high defect density around the ion track (V-2(dense)) and (2) V-2 centers located in regions with a low defect density (V-2(dilute)).
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-43 av 43

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy