Defects in MBE-grown Silicon Epilayers Studied with Variable-Energy Positrons

1989 ◽  
Vol 163 ◽  
Author(s):  
P.J. Simpson ◽  
P.J. Schultz ◽  
I.V. Mitchell ◽  
T.E. Jackman ◽  
G.C. Aers
Keyword(s):  
Depth Distribution ◽  
Surface Defects ◽  
Positron Beam ◽  
Near Surface ◽  
Different Temperatures ◽  
Defects And Impurities ◽  
Non Destructive ◽  
Beam Technique ◽  
Non Destructive Techniques ◽  
Variable Energy

AbstractFew non-destructive techniques are available which provide information regarding defect type, concentration and depth distribution in semiconductors. The variable-energy positron beam technique has recently demonstrated a sensitivity to near surface defects and impurities at low defect concentrations. In the present study, intrinsic silicon (100) epilayers of ~3000 Å thickness grown by MBE at different temperatures were examined by this method for evidence of changing defect concentration and type.

Near-surface defects in hydrogen-plasma-treated boron-doped silicon studied by positron beam spectroscopy

1999 ◽  
Vol 68 (6) ◽  
pp. 643-645 ◽  
Author(s):  
C.E. Gonzalez ◽  
S.C. Sharma ◽  
N. Hozhabri ◽  
D.Z. Chi ◽  
S. Ashok
Keyword(s):  
Surface Defects ◽  
Hydrogen Plasma ◽  
Positron Beam ◽  
Near Surface ◽  
Boron Doped ◽  
Doped Silicon

Positron spectroscopy of bulk and near-surface defects in semiconductors

1989 ◽  
Vol 67 (8) ◽  
pp. 813-817
Author(s):  
P. Hautojārvi
Keyword(s):  
Positron Annihilation ◽  
Positron Lifetime ◽  
Surface Defects ◽  
Positron Beam ◽  
Near Surface ◽  
Slow Positron ◽  
Positron Spectroscopy ◽  
Positron Lifetime Spectroscopy ◽  
Defects In Semiconductors ◽  
Ion Implanted

The use of positron annihilation to study defects in semiconductors is discussed. Positron-lifetime spectroscopy reveals As vacancies in as-grown GaAs and gives information on ionization levels. The vacancy profiles in ion-implanted Si are investigated by slow positron beam.

scholarly journals Non-destructive Testing of Wooden Elements

2021 ◽  
Vol 1203 (3) ◽  
pp. 032058
Author(s):  
Monika Zielińska ◽  
Magdalena Rucka
Keyword(s):  
Surface Defects ◽  
Test Methods ◽  
Ultrasonic Tomography ◽  
Test Results ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Near Surface ◽  
Thermal Techniques ◽  
Ground Penetrating ◽  
Non Destructive

Abstract Examining the condition of wooden elements is crucial from the perspective of proper structure performance. If the deterioration in the internal wood condition, which displays no symptoms visible from the outside, is detected, the further spread of the deterioration can be prevented. Test results often point to the necessity of conducting repairs and, renovations, replacing the structure of wooden beams, or even substituting a significant part of the structure. To achieve acceptable results, test methods should take into account the anisotropic nature of wood, which includes the shape of annual rings, as well as the location of the core in crosssection. To adopt methods based on physical effects, profound knowledge of wood physics is needed, particularly of interdependence. Apart from simple tests such as a visual inspection or tapping that are used to determine near-surface defects, non-destructive testing (NDT) plays an important role in the process. This paper presents the methods of non-destructive testing of wooden elements. These methods include tests conducted with ground penetrating radar (GPR), thermal techniques, microwaves, acoustic emission, ultrasonic tomography, and X-ray tomography. The paper summarises the use of non-destructive methods, indicating their advantages, disadvantages as well as some limitations.

scholarly journals A new approach to near-surface positron annihilation analysis of ion irradiated ferritic alloys

2021 ◽  
Author(s):  
Vladimir Krsjak ◽  
Petr Hruška ◽  
Jarmila Degmova ◽  
Stanislav Sojak ◽  
Pavol Noga ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Ion Beam ◽  
Positron Beam ◽  
Ion Beam Irradiation ◽  
Near Surface ◽  
Slow Positron ◽  
New Approach ◽  
Ferritic Alloys ◽  
Positron Annihilation Lifetime ◽  
Variable Energy

The present work provides an innovative approach to the near-surface slow-positron-beam (SPB) study of structural materials exposed to ion-beam irradiation. This approach enables the use of variable-energy positron annihilation lifetime...

Investigation of Near Surface Defects by Variable-Energy Positron Lifetime Spectroscopy

1992 ◽  
Vol 105-110 ◽  
pp. 1459-1462 ◽  
Author(s):  
Ryoichi Suzuki ◽  
Yoshinori Kobayashi ◽  
Tomohisa Mikado ◽  
Hideaki Ohgaki ◽  
M. Chiwaki ◽  
...  
Keyword(s):  
Positron Lifetime ◽  
Surface Defects ◽  
Near Surface ◽  
Positron Lifetime Spectroscopy ◽  
Variable Energy

scholarly journals Degradation Assessment of Polyethylene-Based Material Through Electrical and Chemical-Physical Analyses

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 650 ◽  
Author(s):  
Simone Vincenzo Suraci ◽  
Davide Fabiani ◽  
Laura Mazzocchetti ◽  
Loris Giorgini
Keyword(s):  
Thermal Analyses ◽  
Polymeric Materials ◽  
Degradation Mechanisms ◽  
Electrical Measurements ◽  
Oxidation Induction Time ◽  
Chemical Measurements ◽  
Different Temperatures ◽  
Non Destructive ◽  
Non Destructive Techniques

The usability of any material hinges upon its stability over time. One of the major concerns, focusing on polymeric materials, is the degradation they face during their service life. The degradation mechanisms are deeply influenced by the aging temperature to which the material is subjected. In this paper, low-density polyethylene (LDPE) flat specimens were thermally aged under two different temperatures (90 °C and 110 °C) and analyzed. Specimens were characterized through both the most common mechanical and chemical measurements techniques (e.g., tensile stress, thermal analyses, oxidation induction time) and electrical measurements (dielectric spectroscopy, in particular), which are examples of non-destructive techniques. As a result, a very spread characterization of the polyethylene-based materials was obtained and a very good correlation was found to exist between these different techniques, highlighting the possibility of following the aging degradation development of polymers through electrical non-destructive techniques.

A variable-energy pulsed positron beam as a non destructive probe for semiconductor materials

1994 ◽  
pp. 725-728
Author(s):  
R. Suzuki ◽  
T. Mikado ◽  
H. Ohgaki ◽  
M. Chiwaki ◽  
T. Yamazaki ◽  
...  
Keyword(s):  
Positron Beam ◽  
Semiconductor Materials ◽  
Non Destructive ◽  
Variable Energy

Impact of New Imaging Non Destructive Methods in Testing and Monitoring of Composite and Metallic Components

2013 ◽  
Author(s):  
Henri Walaszek
Keyword(s):  
Pressure Vessel ◽  
Surface Defects ◽  
Ultrasonic Inspection ◽  
Destructive Testing ◽  
Near Surface ◽  
Ultrasonic Methods ◽  
Processing Information ◽  
Major Trend ◽  
Mechanical Components ◽  
Non Destructive

The non-destructive testing techniques (NDT) are now undergoing significant changes associated with the development of new sensors and digital techniques for storing and processing information. Thus, new ultrasonic methods now provide a view of the entire component in the form of a traceable image. These new methods include ultrasonic TOFD methods (to inspect metal products), and the Phased Array method (metallic and composite products), which can image the inside of components. The simulation of ultrasonic testing brings a strong contribution in ultrasonic inspection preparation. Another major trend of the development of NDT methods is the rise of active thermal infrared methods, enabling high resolution imaging of surface and near surface defects of components. A remarkable application of new radiographic technology consists also in Computed Tomography, which now allows 3D imaging within the mechanical components. These technologies are now available in the market with affordable prices, to test more reliably and faster the health of mechanical components. Thus, it helps to increase the quality of components, especially in the Pressure Vessel and piping industry, and to improve the safety of industrial pressure equipment. Developments in the more advanced testing methods are presented, with examples of applications on pressure vessel and piping components.

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