The depth profiles of ion implantation induced vacancy-type defects probed by a monoenergetic positron beam

AbstractThe formation of nanovoids in Si(100) and MgO(100) by 3He ion implantation has been studied. Contrary to Si in which the voids are generally almost spherical, in MgO nearly perfectly rectangular nanosize voids are created. Recently, the 2D-ACAR setup at the Delft Positron Research Center has been coupled to the intense reactor-based variable-energy positron beam POSH. This allows a new method of monitoring thin layers containing nanovoids or defects by depth-selective high-resolution positron beam analysis. The 2D-ACAR spectra of Si with a buried layer of nanocavities reveal the presence of two additional components, the first related to para-positronium (p-Ps) formation in the nanovoids, and a second one most likely related to unsaturated Si-bonds at the internal surface of the voids. The positronium is present in excited kinetic states with an average energy of 0.3 eV. Refilling of the cavities by means of low dose 3He implantation (1×1014 cm−2) followed by annealing reduces the formation of Ps and the width of the Ps peak in the ACAR spectrum. This width reduction is due to collisions of Ps with He atoms in the voids. In MgO, p-Ps formed with an initial energy of ~3 eV shows a final average energy of 1.6 eV at annihilation due to collisions with the cavity walls. Possibilities of this new, non-destructive method of monitoring the sizes of cavities and the evolution of nanovoid layers will be discussed.

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Defect Formation by Ion Implantation in Cz-Si Studied by a Monoenergetic Positron Beam

MRS Proceedings ◽

10.1557/proc-262-1061 ◽

1992 ◽

Vol 262 ◽

Author(s):

A. Uedono ◽

Y. Ujihira ◽

L. Wei ◽

Y. Tabuki ◽

S. Tanigawa ◽

...

Keyword(s):

Oxygen Vacancy ◽

Ion Implantation ◽

Defect Formation ◽

Positron Beam ◽

Low Energy ◽

Doppler Broadening ◽

Positron Energy ◽

Annealing Experiments ◽

Incident Positron ◽

Ion Implanted

ABSTRACTVacancy-type defects in ion implanted Si were studied by a monoenergetic positron beam. The depth-distributions of the defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. The results showed that a size of vacany-clusters introduced by 150-keV P+-ion implantation was found to be smaller than that introduced by 2-MeV P+-ion implantation. This was attributed to an overlap of collision cascades in low-energy (150 keV) ion implanted specimens. From isochronal annealing experiments for 80-keV B+- and 150-keV P+-ion implanted specimens, the defected region was removed by 1200 °C annealing, however, for 2-MeV P+-implanted specimen, two-types of oxygen-vacancy complexes were found to coexist even after 1200 °C annealing.

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Zirconium-ion implantation of zircaloy-4 investiged by slow positron beam

Acta Physica Sinica ◽

10.7498/aps.56.6543 ◽

2007 ◽

Vol 56 (11) ◽

pp. 6543

Author(s):

Hao Xiao-Peng ◽

Wang Bao-Yi ◽

Yu Run-Sheng ◽

Wei Long

Keyword(s):

Ion Implantation ◽

Positron Beam ◽

Slow Positron

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Plasma ion implantation of nitrogen into silicon: Characterization of the depth profiles of implanted ions

Journal of Applied Physics ◽

10.1063/1.357072 ◽

1994 ◽

Vol 76 (10) ◽

pp. 5666-5675 ◽

Cited By ~ 32

Author(s):

John J. Vajo ◽

John D. Williams ◽

Ronghua Wei ◽

Robert G. Wilson ◽

Jesse N. Matossian

Keyword(s):

Ion Implantation ◽

Depth Profiles

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Stoichiometric Disturbance in InP Measured During Ion Implantation Process

MRS Proceedings ◽

10.1557/proc-27-371 ◽

1983 ◽

Vol 27 ◽

Cited By ~ 4

Author(s):

D. Haberland ◽

P. Harde ◽

H. Nelkowski ◽

W. Schlaak

Keyword(s):

Quantitative Analysis ◽

Ion Implantation ◽

Target Chamber ◽

Depth Profiles ◽

Preferential Sputtering ◽

Implantation Process ◽

Sputtering Yield ◽

Set Up

ABSTRACTTo measure the sputtered ions during implantation a specially designed UHV-target chamber with a SIMS apparatus was set up. Quantitative analysis are possible with an Auger spectrometer. Disturbances in the stoichiometry in InP are measured during implantation of Sn. The enrichment of the doped surface of InP with the lighter component phoshorus will be discussed in consideration of preferential sputtering and recoil effects during implantation. Measured depth profiles of Sn in InP will be compared with calculated distributions on condition that sputtering takes place. The sputtering yield of InP bombarded by 120 keV Sn+ is 17±5.

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Quantitation of Secondary Ion Mass Spectrometry (SIMS) for HgCdTe.

MRS Proceedings ◽

10.1557/proc-25-657 ◽

1983 ◽

Vol 25 ◽

Cited By ~ 3

Author(s):

Lawrence E. Lapides ◽

George L. Whiteman ◽

Robert G. Wilson

Keyword(s):

Mass Spectrometry ◽

Ion Implantation ◽

Ionization Potential ◽

Electron Affinity ◽

Secondary Ion Mass Spectrometry ◽

Relative Sensitivity ◽

Depth Profiles ◽

Ion Mass Spectrometry ◽

Sensitivity Factors ◽

Secondary Ion

ABSTRACTQuantitative depth profiles of impurities in LPE layers of HgCdTe have been determined using relative sensitivity factors calculated from ion implantation profiles. Standards were provided for Li, Be, B, C, F, Na, Mg, Al, Si, P, S, Cl, Cu, Ga, As, Br, and In. Relative sensitivity factors as a function of ionization potential for O2+ primary ion SIMS and electron affinity for Cs+ primary ion SIMS have been calculated in order to extend quantitation to elements not yet implanted. Examples of depth profiles for implant standards and unimplanted layers are given.

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Cation Transport and Surface Reconstruction in Lanthanum Doped Strontium Titanate at High Temperatures

MRS Proceedings ◽

10.1557/proc-756-ee3.1 ◽

2002 ◽

Vol 756 ◽

Author(s):

Karsten Gömann ◽

Günter Borchardt ◽

Anissa Gunhold ◽

Wolfgang Maus-Friedrichs ◽

Bernard Lesage ◽

...

Keyword(s):

Ion Implantation ◽

Single Crystals ◽

Surface Reconstruction ◽

Strontium Titanate ◽

Cation Transport ◽

Tracer Diffusion ◽

Ex Situ ◽

Spectroscopic Methods ◽

Time Dependency ◽

Depth Profiles

ABSTRACTTracer diffusion experiments were carried out in synthetic air at 1573 K in SrTiO3(100) and (110) single crystals, which were either undoped or doped with up to 1 at.% La, respectively. Tracer sources of 139La and 142Nd were applied by ion implantation. The resulting depth profiles were measured by SIMS. The reconstruction of the surface was monitored ex-situ using microscopic and spectroscopic methods including SEM, EPMA, and AFM. The measured tracer diffusivities show no dependency on orientation. The tracer diffusion takes place via cation vacancies. Under oxidizing conditions the dopant is compensated by Sr vacancies. Hence the diffusion is increasing strongly with La concentration. The observed time dependency of the diffusivities may be related to a space charge layer postulated by the current defect chemistry model for donor doped SrTiO3. At high dopant concentrations annealing leads to segregation of bulk La to the surface. La is not significantly incorporated into the secondary crystallites at the surface which consist almost entirely of Sr and O.

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Study of Microvoids in High-Rate a-Si:H Using Positron Annihilation

MRS Proceedings ◽

10.1557/proc-467-525 ◽

1997 ◽

Vol 467 ◽

Author(s):

X. Zou ◽

D. P. Webb ◽

S. H. Lin ◽

Y. W. Lam ◽

Y. C. Chan ◽

...

Keyword(s):

Thin Films ◽

Positron Annihilation ◽

Surface Region ◽

Positron Beam ◽

High Rate ◽

Doppler Broadening ◽

Slow Positron ◽

Depth Profiles ◽

Vacancy Type Defect ◽

Low Rate

ABSTRACTIn this paper, we have carried out the positron annihilation measurement on high-rate and low-rate a-Si:H thin films deposited by PECVD. By means of the slow positron beam Doppler-broadening technique, the depth profiles of microvoids in a-Si:H have been determined. We have also studied the vacancy-type defect in the surface region in high-rate grown a-Si:H, making comparison between high-rate and low-rate a-Si:H. By plotting S and W parameters in the (S, W) plane, we have shown that the vacancies in all of the high-rate and low-rate deposited intrinsic samples, and in differently doped low-rate samples are of the same nature.

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Study of the Photocatalytic Property of Polysulfone Membrane Incorporating TiO2 Nanoparticles

Journal of Molecular and Engineering Materials ◽

10.1142/s2251237317500058 ◽

2017 ◽

Vol 05 (02) ◽

pp. 1750005 ◽

Cited By ~ 4

Author(s):

Xingxing Chen ◽

Weiqi Zhou ◽

Zhe Chen ◽

Lei Yao

Keyword(s):

Electrochemical Impedance ◽

Uv Light ◽

Photocatalytic Property ◽

Positron Beam ◽

Hybrid Membranes ◽

Polysulfone Membrane ◽

Photocatalytic Ability ◽

Depth Profiles ◽

Vis Spectroscopy ◽

Photocatalytic Activities

In order to investigate the effect of the incorporated nanoparticles on the photocatalytic property of the hybrid membranes, the uncovered and covered polysulfone/TiO2 hybrid membranes were prepared. Positron annihilation [Formula: see text]-ray spectroscopy coupled with a positron beam was utilized to examine the depth profiles of the two membranes. The photocatalytic activities of the membranes were evaluated by the degradation of Rhodamine B (RhB) aqueous solution under the irradiation of Xe lamp. UV-Vis spectroscopy was applied to study the UV transmission through the polysulfone layer. Electrochemical impedance spectroscopy was used to detect the photo-generated charges by the covered membrane during the irradiation. It can be found that UV light can penetrate through the covered layer (about 230[Formula: see text]nm), and the incorporated nanoparticles can still generate charges under irradiation, which endows the photocatalytic ability of the covered membrane.

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