The Lack of Trapping Centers for Positrons at the Interface of W/Si System and the Investigation of the Depletion Layer in the Schottky Barrier by Positrons as Test Charge Simulating Holes

1992 ◽  
Vol 262 ◽  
Author(s):  
S. Tanigawa ◽  
Y. Tabuki ◽  
L. Wei ◽  
K. Hinode ◽  
N. Kobayashi ◽  
...  
Keyword(s):  
Electric Field ◽  
Schottky Barrier ◽  
Positron Beam ◽  
Interfacial Phenomena ◽  
Doppler Broadening ◽  
Dc Magnetron Sputtering ◽  
Positron Energy ◽  
Test Charge ◽  
P Type ◽  
Incident Positron

ABSTRACTInterfacial phenomena in the W-Si systems were studied by a monoenergetic positron beam. Doppler broadening profiles of the positron annihilation were measured as a function of incident positron energy. Tungsten thin films of 100 nm in thickness were deposited on p-type, 10 »cm Cz-grown Si wafers with (100) orientation by the DC magnetron sputtering method. Specimens were annealed at various temperatures in order to form suicides. It was found that the position of the interface of both W/Si and W silicide/Si is very different from the position expected from a simple situation neglecting the effect of electric field on the diffusion of positrons. This fact arouse the utility of positrons as a test charge to probe directly the electric field gradient in the Schottky barrier.

Defects Introduced by Low Dose Be-Implantation Probed by a Monoenergetic Positron Beam

1992 ◽  
Vol 262 ◽  
Author(s):  
A. Uedono ◽  
Y. Ujihira ◽  
L. Wei ◽  
Y. Tabuki ◽  
S. Tanigawa ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Positron Annihilation ◽  
Low Dose ◽  
Positron Beam ◽  
Doppler Broadening ◽  
Positron Energy ◽  
P Type ◽  
Incident Positron ◽  
Depth Distributions

ABSTRACTVacancy-type defects in 60-keV Be+-implanted GaAs and InP were studied by a monoenergetic positron beam. The depth distributions of vacancy-type defects were obtained from measurements of Doppler broadening profiles of the positron annihilation as a function of incident positron energy. Vacancy-type defects introduced by ion implantation were observed in n-type GaAs. For p-type GaAs, however, this was not the case. This can be attributed to the recombination of vacancy-type defects and pre-existed interstitial-type defects in p-type GaAs. The defects induced by ion implantation in InP were also studied.

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

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.

scholarly journals The External Electric Field-Induced Tunability of the Schottky Barrier Height in Graphene/AlN Interface: A Study by First-Principles

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1794
Author(s):  
Xuefei Liu ◽  
Zhaocai Zhang ◽  
Bing Lv ◽  
Zhao Ding ◽  
Zijiang Luo
Keyword(s):  
Electric Field ◽  
Schottky Barrier ◽  
External Electric Field ◽  
Barrier Height ◽  
Density Functional ◽  
Schottky Barrier Height ◽  
Schottky Contact ◽  
Valence Band Maximum ◽  
Charge Analysis ◽  
P Type

Graphene-based van der Waals (vdW) heterojunction plays an important role in next-generation optoelectronics, nanoelectronics, and spintronics devices. The tunability of the Schottky barrier height (SBH) is beneficial for improving device performance, especially for the contact resistance. Herein, we investigated the electronic structure and interfacial characteristics of the graphene/AlN interface based on density functional theory. The results show that the intrinsic electronic properties of graphene changed slightly after contact. In contrast, the valence band maximum of AlN changed significantly due to the hybridization of Cp and Np orbital electrons. The Bader charge analysis showed that the electrons would transfer from AlN to graphene, implying that graphene would induce acceptor states. Additionally, the Schottky contact nature can be effectively tuned by the external electric field, and it will be tuned from the p-type into n-type once the electric field is larger than about 0.5 V/Å. Furthermore, the optical absorption of graphene/AlN is enhanced after contact. Our findings imply that the SBH is controllable, which is highly desirable in nano-electronic devices.

Defect Detection in Fe-Cr Alloys with Positron Annihilation Doppler Broadening Spectroscopy

2012 ◽  
Vol 733 ◽  
pp. 270-273 ◽  
Author(s):  
Veronika Sabelová ◽  
Martin Petriska ◽  
Jana Veterníková ◽  
Vladimir Slugeň ◽  
Jarmila Degmová ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Positron Beam ◽  
Quantitative Information ◽  
Structural Defects ◽  
Doppler Broadening ◽  
Positron Energy ◽  
Open Volume ◽  
Order Of Magnitude ◽  
Radiation Induced ◽  
Induced Defects

Positron annihilation Doppler broadening spectroscopy (DBS) has been used for the detection of structural defects in Fe-9wt%Cr (Fe-9Cr) alloy in the as-prepared and implanted states. Defects were created by He and H ion implantation with a kinetic energy of 250 keV. DBS is a non-destructive method and is a unique tool for the observation of open volume defects like vacancies and vacancy clusters in solids. A positron beam with variable positron energy was used for the measurement of defect depth profiles up to 1.5 µm. The obtained results provide qualitative and semi-quantitative information about radiation induced defects and their chemical environment. Although the collision damage from helium implantation was one order of magnitude higher than for the case of hydrogen, the changes in S and W parameters are much less significant, probably due to considerably lower mobility of helium in the implanted materials, which results in helium capture by the created open volume defects.

Evaluation of Vacancy-Type Defects in Simox Substrates by a Slow Positron Beam and a Pulsed Positron Beam

1992 ◽  
Vol 262 ◽  
Author(s):  
H. Kametani ◽  
H. Akiyama ◽  
Y. Yamaguchi ◽  
M. Koumaru ◽  
L. Wei ◽  
...  
Keyword(s):  
Positron Lifetime ◽  
Silicon Layer ◽  
Positron Beam ◽  
High Dose ◽  
Positron Energy ◽  
Slow Positron ◽  
Depth Profiles ◽  
Positron Beams ◽  
Non Destructive ◽  
Incident Positron

ABSTRACTSlow/monoenergetic positron beams and pulsed positron beams have been used as a non-destructive probe to investigate vacancy-type defects in SIMOX substrates which were formed by high - dose oxygen implantation and high-temperature annealing. To obtain depth profiles of vacancy-type defects, a positron beam in the 0–30keV energy range was used. Doppler broadened annihilation spectrum and positron lifetime were measured as a function of incident positron energy. These measurements show the following results; vacancy -type defects exist near the surface of the top silicon layer even if the specimen was analyzed as defect -free Silicon by XTEM, and in the case of the as-implanted specimen, cavities in diameter of about 50–200A are created in the top silicon layer and they include high pressure gases.

scholarly journals Schottky barrier and attenuation length for hot hole injection in nonepitaxial Au on p-type GaAs

2012 ◽  
Vol 30 (4) ◽  
pp. 04E110 ◽  
Author(s):  
Ilona Sitnitsky ◽  
John J. Garramone ◽  
Joseph Abel ◽  
Peng Xu ◽  
Steven D. Barber ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Hole Injection ◽  
Attenuation Length ◽  
P Type

Resonant Positron Annihilation on Molecules

2008 ◽  
Vol 607 ◽  
pp. 9-16 ◽  
Author(s):  
J.A. Young ◽  
C.M. Surko
Keyword(s):  
Positron Annihilation ◽  
Binding Energies ◽  
Current Understanding ◽  
Positronium Atom ◽  
Feshbach Resonances ◽  
Positron Energy ◽  
Incident Positron

At incident positron energies below the threshold for positronium atom formation, there are many cases in which annihilation rates for molecules are far in excess of that possible on the basis of simple two-body collisions. We now understand that this phenomenon is due to positron attachment to molecules mediated by vibrational Feshbach resonances. The attachment enhances greatly the overlap of the positron with molecular electrons and hence increases the probability of annihilation. Furthermore, measurements of the annihilation spectra as a function of incident positron energy provide a means of measuring positron-molecule binding energies. In this paper we present an overview of our current understanding of this process, highlighting key results and discussing outstanding issues that remain to be explained.

Dislocation scatterings in p-type Si1−xGexunder weak electric field

2015 ◽  
Vol 26 (49) ◽  
pp. 495201 ◽  
Author(s):  
Ji-Hyun Hur ◽  
Sanghun Jeon
Keyword(s):  
Electric Field ◽  
Weak Electric Field ◽  
P Type
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