Defect Production Mechanisms During keV Ion Irradiation: Results of Computer Simulations

1994 ◽  
Vol 373 ◽  
Author(s):  
R.S. Averback ◽  
Mai Ghaly ◽  
Huilong Zhu
Keyword(s):  
Computer Simulations ◽  
Convective Flow ◽  
Energy Deposition ◽  
Ion Irradiation ◽  
Md Simulations ◽  
Defect Production ◽  
Atomic Mixing ◽  
Damage Processes ◽  
Production Mechanisms ◽  
Explosive Event

AbstractMD simulations have been employed to investigate damage processes during keV bombardment of metal targets. For self-ion irradiations of Au, Cu, and Pt in the range of 5-20 keV, we have found that both the amount and the character of the damage created in the surface depends sensitively on the details of the energy deposition along individual ion trajectories. In all of these cases, significantly more damage is produced and more atomic mixing takes place relative to corresponding recoil events in the crystal interior. In some cases, enormous craters are formed in an explosive event, while in others a convective flow of atoms to the surface leaves dislocations behind. The results of these simulations will be summarized and their significance for damage studies of ion irradiated materials, discussed.

Surface Damage During Kev Ion Irradiation: Results of Computer Simulations

1995 ◽  
Vol 388 ◽  
Author(s):  
R.S. Averback ◽  
Mai Ghaly ◽  
Huilong Zhu
Keyword(s):  
Energy Deposition ◽  
Ion Irradiation ◽  
Surface Damage ◽  
Md Simulations ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Individual Ion ◽  
Atomic Mixing ◽  
Damage Processes ◽  
Explosive Event

AbstractMD simulations have been employed to investigate damage processes near surfaces during keV bombardment of metal targets. For self-ion implantation of au, Cu, and Pt in the range of 5-20 keV, we have found that the proximity of the surface leads to significantly more damage and atomic mixing in comparison to recoil events occurring in the crystal interior. IN some cases, large craters are formed in a micro-explosive event, while in others a convective flow of atoms to the surface creates adatoms and leaves dislocations behind. Both the amount damage created in the surface and its morphology depend sensitively on the details of the energy deposition along individual ion trajectories. the results of these simulations will be summarized and compared to recent scanning tunneling microscopy studies of individual ion impacts in Pt and Ge.

Monte Carlo Simulation of the Initial Disordering Rate of Cu3Au Under Ion Irradiation

1998 ◽  
Vol 527 ◽  
Author(s):  
L.C. Wei ◽  
E. Lang ◽  
M. Ghaly ◽  
P. Bellon ◽  
R. S. Averback
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Temperature Dependence ◽  
Computer Simulations ◽  
Monte Carlo Methods ◽  
Ion Irradiation ◽  
Atomic Mixing ◽  
Present Simulation

ABSTRACTThe temperature dependence of disordering of Cu3Au during ion irradiation has been investigated by computer simulations using MONTE CARLO methods. The investigation was motivated by peculiar experimental observations that the initial disordering rate begins to decrease above ~300 K, which can be explained by vacancies just becoming mobile at that temperature, but then at ~ 475 K, it reaches a minimum and then increases rapidly as the temperature is further increased, up to the order-disorder temperature. The present simulation shows that this behavior can be understood in terms of temperatures dependencies in both atomic mixing in the cascade and the efficiency of vacancy annealing of disorder as the vacancies diffuse out of the cascade.

scholarly journals Ion tracks in silicon formed by much lower energy deposition than the track formation threshold

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Amekura ◽  
M. Toulemonde ◽  
K. Narumi ◽  
R. Li ◽  
A. Chiba ◽  
...  
Keyword(s):  
Nuclear Energy ◽  
Energy Deposition ◽  
Ion Irradiation ◽  
High Energy ◽  
Electronic Energy ◽  
Synergy Effect ◽  
Ion Tracks ◽  
Track Formation ◽  
Low Energies ◽  
High Energy Ions

AbstractDamaged regions of cylindrical shapes called ion tracks, typically in nano-meters wide and tens micro-meters long, are formed along the ion trajectories in many insulators, when high energy ions in the electronic stopping regime are injected. In most cases, the ion tracks were assumed as consequences of dense electronic energy deposition from the high energy ions, except some cases where the synergy effect with the nuclear energy deposition plays an important role. In crystalline Si (c-Si), no tracks have been observed with any monomer ions up to GeV. Tracks are formed in c-Si under 40 MeV fullerene (C60) cluster ion irradiation, which provides much higher energy deposition than monomer ions. The track diameter decreases with decreasing the ion energy until they disappear at an extrapolated value of ~ 17 MeV. However, here we report the track formation of 10 nm in diameter under C60 ion irradiation of 6 MeV, i.e., much lower than the extrapolated threshold. The diameters of 10 nm were comparable to those under 40 MeV C60 irradiation. Furthermore, the tracks formed by 6 MeV C60 irradiation consisted of damaged crystalline, while those formed by 40 MeV C60 irradiation were amorphous. The track formation was observed down to 1 MeV and probably lower with decreasing the track diameters. The track lengths were much shorter than those expected from the drop of Se below the threshold. These track formations at such low energies cannot be explained by the conventional purely electronic energy deposition mechanism, indicating another origin, e.g., the synergy effect between the electronic and nuclear energy depositions, or dual transitions of transient melting and boiling.

Atomic Mixing Induced by Ion Irradiation of V/Cu Multilayers

2020 ◽  
Vol 37 (3) ◽  
pp. 036101
Author(s):  
Yan-Bin Sheng ◽  
Hong-Peng Zhang ◽  
Tie-Long Shen ◽  
Kong-Fang Wei ◽  
Long Kang ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Atomic Mixing

The Effect of Temperature on Defect Production by Displacement Cascades in alpha;-IRON

1996 ◽  
Vol 439 ◽  
Author(s):  
F. Gao ◽  
D. J. Bacon ◽  
P. E. J. Flewitt ◽  
T. A. Lewis
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Irradiation Temperature ◽  
Effect Of Temperature ◽  
Cascade Process ◽  
Thermal Spike ◽  
Defect Production ◽  
Alpha Iron ◽  
Displacement Cascades ◽  
The Continuum

AbstractMolecular dynamics (MD) simulations have been used to study the number and arrangement of defects produced by displacement cascades as functions of irradiation temperature, Tirr, in α-iron. The continuum treatment of heat conduction was used to adjust the temperature of the MD boundary atoms throughout the cascade process. This new hybrid model has been applied to cascades of either 2 or 5 keV at 100K, 400K, 600K and 900K. The number of Frenkel pairs decreases by about 20–30% as Tir increases from 100K to 900K, due to the increase in the lifetime of the thermal-spike phase. The same effect also brings about an increase in the proportion of selfinterstitial atoms that form clusters.

Ion-beam mixing of Ni/Pd layers: II. Thermally assisted regime (>500K)

1988 ◽  
Vol 3 (6) ◽  
pp. 1063-1071 ◽  
Author(s):  
U. G. Akano ◽  
D. A. Thompson ◽  
W. W. Smeltzer ◽  
J. A. Davies
Keyword(s):  
Grain Boundary ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Effective Diffusivity ◽  
Bilayer Films ◽  
Diffusion Analysis ◽  
The Mean ◽  
Atomic Mixing ◽  
Lattice Diffusivity

Atomic mixing in Ni/Pd bilayer films due to 120 keV Ar+ irradiation in the thermally assisted regime (523−673 K) has been measured, in situ, using Rutherford backscattering with 2.0 MeV 4He+ ions. The mean diameter of grains in these polycrystallinc films increased from 10 to 60 nm, following Ar+ bombardment at 573 K. Initial mixing was rapid due to grain boundary diffusion and incorporation of the metal solute into the solvent metal matrix by grain growth; this mixing stage was essentially complete within 10 min for annealed films or after an Ar+ dose of 4 × 1015 cm−2 in irradiated films (10 min irradiation). No further measurable mixing occurred in the annealed, unirradiated films. For the irradiated samples the initial rapid mixing (6−35 atoms/ion) was followed by a slower mixing stage of 0.7–1.8 atoms/ion for irradiation doses of up to 2.5 × 1016 Ar+ cm−2. The Ar+ bombardment gave rise to much smaller mixing levels when the Pd films were deposited on large-grain or single-crystal Ni. A diffusion analysis demonstrates that the effective diffusivity, Deff, for ion-irradiation-enhanced mixing in the thermally assisted regime satisfied the relation Dl < Deff < DB, where the ratio of the grain boundary to lattice diffusivity was DB/Dl > 106.

Point Defects in GaAs and Other Semiconductors

1992 ◽  
Vol 279 ◽  
Author(s):  
P. Ehrhart ◽  
K. Karsten ◽  
A. Pillukat
Keyword(s):  
Optical Absorption ◽  
Point Defects ◽  
Irradiation Dose ◽  
Ion Irradiation ◽  
Strongly Correlated ◽  
X Ray Diffraction ◽  
Defect Production ◽  
Annealing Stage ◽  
X Ray ◽  
Interstitial Atoms

ABSTRACTIn order to understand the properties of intrinsic point defects and their interactions at high defect concentrations GaAs wafers were irradiated at 4.5 K with 3 MeV electrons up to a dose of 4.1019 e-/cm2. The irradiated samples were investigated by X-ray Diffraction and optical absorption spectrocopy. The defect production increases linearly with irradiation dose and characteristic differences are observed for the two sublattices. The Ga-Frenkel pairs are strongly correlated and are characterized by much larger lattice relaxations (Vrel=2–3 atomic volumes) as compared to the As-Frenkel pairs (Vrel ≈ 1 at.voL). The dominating annealing stage around 300 K is attributed to the mobility of the Ga interstitial atoms whereas the As-interstitial atoms can recombine with their vacancies only around 500 K. These results are compared to those for InP, ZnSe and Ge. Implications for the understanding of the damage after ion irradiation and implantation are discussed.

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