scholarly journals Computational Study of Damage Profiles and Energy Loss of Gallium Ion in Germanium Substrate

2020 ◽  
Vol 6 (1) ◽  
pp. 117-122
Author(s):  
K. Giri ◽  
A. Bhandari
Keyword(s):  
Energy Loss ◽  
Incident Energy ◽  
Computational Study ◽  
Target Displacement ◽  
Collision Process ◽  
Nuclear Stopping ◽  
Germanium Substrate ◽  
Ionic Implantation ◽  
Computational Calculation

Computational calculation of energy loss and study of damage profiles during ionic implantation by gallium ions on germanium had been carried out. The required energies for doping of gallium ion on germanium, in order to obtain maximum damage at 600 Å, were calculated using SRIM; Stopping and Range of Ions in Matter. The ions when implanted independently on germanium causes the production of germanium recoils, vacancy-interstitial pairs, and phonons during the collision process. For 130 keV gallium ion, the energy used for ionization, phonon production and vacancies creation are 37.713 keV (29.01% of incident energy), 90.006 keV (64.29% of incident energy) and 8.71 keV (6.7% of incident energy) respectively. The amount of target displacement, replacement collisions and vacancies were also evaluated. Doping of gallium ions on germanium also reveals that the energy loss due to nuclear stopping was greater than electronic stopping.

scholarly journals Study of damage profiles and energy calculation of arsenic ions during ion implantation on Germanium

BIBECHANA ◽  
2020 ◽  
Vol 17 ◽  
pp. 96-103
Author(s):  
K Giri ◽  
K Kandel
Keyword(s):  
Ion Implantation ◽  
Energy Loss ◽  
Incident Energy ◽  
Surface Hardness ◽  
Energy Calculation ◽  
Target Displacement ◽  
Collision Process ◽  
Nuclear Stopping ◽  
Loss And Damage ◽  
Computational Calculation

Computational calculation of energy loss and damage profiles when implanted by arsenic ions on amorphous germanium during ion implantation had been carried out. The required energies for doping of arsenic ion on germanium, in order to obtain maximum damage at 600 Å, were calculated using SRIM. These ions when implanted on germanium causes the production of germanium recoils, vacancy-interstitial pairs, and phonons during the collision process. For 140 keV arsenic ion, the energy consumption for ionization, phonon production and vacancies creation are 39.634 keV (28.31% of incident energy), 90.888 keV (64.92% of incident energy) and 9.478 keV (6.77% of incident energy), respectively. The amount of target displacement, replacement collisions and vacancies were also evaluated. Doping of arsenic ions on germanium also revealed that the energy loss due to nuclear stopping was greater than electronic stopping. Significantly, surface hardness and electrical conductivity on germanium cannot be improved with calculated energies. BIBECHANA 17 (2020) 96-103

scholarly journals Strain/Damage in Crystalline Materials Bombarded by MeV Ions: Recrystallization of GaAs by High-Dose Irradiation

1984 ◽  
Vol 35 ◽  
Author(s):  
C. R. Wie ◽  
T. Vreeland ◽  
T. A. Tombrello
Keyword(s):  
Surface Layer ◽  
Energy Loss ◽  
Ion Irradiation ◽  
Stopping Power ◽  
High Dose ◽  
Double Crystal ◽  
Saturation Phenomenon ◽  
Nuclear Stopping ◽  
X Ray ◽  
Dose Irradiation

ABSTRACTMeV ion irradiation effects on semiconductor crystals, GaAs(100) and Si (111) and on an insulating crystal CaF2 (111) have been studied by the x-ray rocking curve technique using a double crystal x-ray diffractometer. The results on GaAs are particularly interesting. The strain developed by ion irradiation in the surface layers of GaAs (100) saturates to a certain level after a high dose irradiation (typically 1015/cm2), resulting in a uniform lattice spacing about 0.4% larger than the original spacing of the lattice planes parallel to the surface. The layer of uniform strain corresponds in depth to the region where electronic energy loss is dominant over nuclear collision energy loss. The saturated strain level is the same for both p-type and n-type GaAs. In the early stages of irradiation, the strain induced in the surface is shown to be proportional to the nuclear stopping power at the surface and is independent of electronic stopping power. The strain saturation phenomenon in GaAs is discussed in terms of point defect saturation in the surface layer.An isochronal (15 min.) annealing was done on the Cr-doped GaAs at temperatures between 200° C and 700° C. The intensity in the diffraction peak from the surface strained layer jumps at 200° C < T ≤ 300° C. The strain decreases gradually with temperature, approaching zero at T ≤ 500° C.The strain saturation phenomenon does not occur in the irradiated Si. The strain induced in Si is generally very low (less than 0.06%) and is interpreted to be mostly in the layers adjacent to the maximum nuclear stopping region, with zero strain in the surface layer. The data on CaF2 have been analysed with a kinematical x-ray diffraction theory to get quantitative strain and damage depth profiles for several different doses.

Collision site effect on the radiation dynamics of cytosine induced by proton

2022 ◽  
Author(s):  
Xu Wang ◽  
Zhi-Ping Wang ◽  
Feng-Shou Zhang ◽  
Chao-Yi Qian
Keyword(s):  
Energy Loss ◽  
Incident Energy ◽  
Density Functional ◽  
Degrees Of Freedom ◽  
Site Effect ◽  
Low Energy ◽  
Microscopic Mechanism ◽  
Scattering Angle ◽  
Fragment Mass ◽  
Dynamics Simulations

Abstract By combing the time-dependent density functional calculations for electrons with molecular dynamics simulations for ions (TDDFT-MD) nonadiabatically in real time, we investigate the microscopic mechanism of collisions between cytosine and low-energy protons with incident energy ranging from 150 eV to 1000 eV. To explore the effects of the collision site and the proton incident energy on irradiation processes of cytosine, two collision sites are specially considered, which are N and O both acting as the proton receptors when forming hydrogen bonds with guanine. Not only the energy loss and the scattering angle of the projectile, but also the electronic and ionic degrees of freedom of the target are identified. It is found that the energy loss of proton increases linearly with the increase of the incident energy in both situations, which are 14.2% and 21.1% of the incident energy respectively. However, the scattering angles show different behaviors in these two situations when the incident kinetic energy increases. When proton collides with O, the scattering angle of proton is larger and the energy lost is more, while proton captures less electrons from O. The calculated fragment mass distribution shows the high counts of the fragment mass of 1, implying the production of H+ fragment ion from cytosine even for proton with the incident energy lower than keV. Furthermore, the calculated results show that N on cytosine is easier to be combined with low-energy protons to form NH bonds than O.

An experimental and computational study of the post-collisional flow induced by an impulsively rotated sphere

2019 ◽  
Vol 881 ◽  
pp. 772-793 ◽  
Author(s):  
Sophie A. W. Calabretto ◽  
James P. Denier ◽  
Benjamin Levy
Keyword(s):  
Boundary Layer ◽  
Particle Image Velocimetry ◽  
Boundary Layers ◽  
Recirculation Zone ◽  
Particle Image ◽  
Computational Study ◽  
Collision Process ◽  
Image Velocimetry ◽  
Unsteady Boundary Layers ◽  
Quiescent Fluid

The unsteady flow due to a sphere, immersed in a quiescent fluid, and suddenly rotated, is a paradigm for the development of unsteady boundary layers and their collision. Such a collision arises when the boundary layers on the surface of the sphere are advected towards the equator, where they collide, serving to generate a radial jet. We present the first particle image velocimetry measurements of this collision process, the resulting starting vortex and development of the radial jet. Coupled with new computations, we demonstrate that the post-collision steady flow detaches smoothly from the sphere’s surface, in qualitative agreement with the analysis of Stewartson (Grenzschichtforschung/Boundary Layer Research (ed. H. Görtler), Springer, 1958, pp. 60–70), with no evidence of a recirculation zone, contrary to the conjectured structure of Smith & Duck (Q. J. Mech. Appl. Maths, vol. 20, 1977, pp. 143–156).

Thickness Measurement by EELS

1985 ◽  
Vol 43 ◽  
pp. 398-399
Author(s):  
R. F. Egerton ◽  
S. C. Cheng
Keyword(s):  
Energy Loss ◽  
Electron Energy Loss Spectroscopy ◽  
Incident Energy ◽  
Mean Free Path ◽  
Thickness Measurement ◽  
Loss Peak ◽  
Wide Range ◽  
Integrated Intensity ◽  
The Mean ◽  
Electron Energy Loss

Electron energy-loss spectroscopy offers a rapid method of estimating the local thickness of a TEM specimen. The best-known procedure requires only measurement of the integrated intensity IO under the zero-loss peak and of the integral It under the whole spectrum (up to some suitable energy loss Δ). The thickness t is obtained from the formula:where λ(β) is the mean free path for inelastic scattering up to some angle β which is determined by the collection aperture (e.g. objective aperture in CTEM). In agreement with previous work we find that Eq. (1) is applicable over a wide range of thickness, typically 10-500 nm for EO = 100keV incident energy; see Fig. 1. Some deviation at large thickness might be expected as a result of the angular broadening produced by plural scattering, and because of contributions from electrons elastically scattered through angles greater than β.

A computational study of hydrogen detection by borophene

2017 ◽  
Vol 5 (22) ◽  
pp. 5426-5433 ◽  
Author(s):  
Michal Novotný ◽  
Francisco Javier Domínguez-Gutiérrez ◽  
Predrag Krstić
Keyword(s):  
Molecular Dynamics ◽  
Energy Range ◽  
Incident Energy ◽  
Computational Study ◽  
Transmission Probability ◽  
Quantum Conductance ◽  
Hydrogen Detection ◽  
Classical Molecular Dynamics

We present a quantum-classical molecular dynamics study of hydrogen irradiation of a single corrugated boron sheet in the incident energy range of 0.25–100 eV and report the resulting reflection, adsorption, and transmission probability, as well as quantum conductance in function of hydrogen coverage.

DEPOSITION OF MASS-SELECTED Ag7 ON Pd(100): FRAGMENTATION AND IMPLANTATION

1996 ◽  
Vol 03 (01) ◽  
pp. 949-954 ◽  
Author(s):  
G. VANDONI ◽  
C. FÉLIX ◽  
R. MONOT ◽  
J. BUTTET ◽  
C. MASSOBRIO ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Incident Energy ◽  
Silver Cluster ◽  
Cluster Ions ◽  
Embedded Atom Method ◽  
Collision Process ◽  
Embedded Atom ◽  
Molecular Dynamics Calculations ◽  
Impact Energies ◽  
The Impact

Mass-selected silver-cluster ions [Formula: see text] with an incident energy of 2.86 eV/atom and of 13.6 eV/atom are directed on a well-prepared Pd(100) surface, which is probed with thermal-energy atom (helium) scattering (TEAS), before, during, and after the deposition, yielding information on the collision process. We find that part of the cluster atoms are implanted into the surface layer, the fraction depending on the impact energy. Considerable fragmentation is present at both impact energies. Molecular dynamics calculations based on embedded atom method (EAM) potentials are used to model the collision process. These calculations confirm qualitatively the experimental results.

On the inadequate equilibrium accomplished in mass asymmetric reactions at intermediate energies

2018 ◽  
Vol 33 (34) ◽  
pp. 1850201 ◽  
Author(s):  
Deepshikha ◽  
Suneel Kumar
Keyword(s):  
Molecular Dynamics ◽  
Incident Energy ◽  
Asymmetric Reactions ◽  
Quantum Molecular Dynamics ◽  
Dynamics Model ◽  
Nuclear Stopping ◽  
Mass Asymmetry ◽  
Intermediate Energies

The isospin-dependent quantum molecular dynamics model has been employed to explore the participant–spectator matter. Simulations have been carried out over the whole colliding geometry for mass asymmetric reactions. The degree of nuclear stopping depends strongly on the mass of the projectile, incident energy as well as on the colliding geometry of the reaction. It has been predicted that effect of mass asymmetry can be compensated by varying the colliding geometry.

Sign in / Sign up

Export Citation Format

Share Document