doi = "doi:10.1016/j.nimb.2006.12.118",
publisher = "ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM,
NETHERLANDS",
+ abstract = "Periodically arranged, selforganised, nanometric,
+ amorphous precipitates have been observed after
+ high-fluence ion implantations into solids for a number
+ of ion/target combinations at certain implantation
+ conditions. A model describing the ordering process
+ based on compressive stress exerted by the amorphous
+ inclusions as a result of the density change upon
+ amorphisation is introduced. A Monte Carlo simulation
+ code, which focuses on high-fluence carbon
+ implantations into silicon, is able to reproduce
+ experimentally observed nanolamella distributions as
+ well as the formation of continuous amorphous layers.
+ By means of simulation, the selforganisation process
+ becomes traceable and detailed information about the
+ compositional and structural state during the ordering
+ process is obtained. Based on simulation results, a
+ recipe is proposed for producing broad distributions of
+ ordered lamellar structures.",
}
@Article{zirkelbach2006,
doi = "doi:10.1016/j.nimb.2005.08.162",
publisher = "ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM,
NETHERLANDS",
+ abstract = "High-dose ion implantation of materials that undergo
+ drastic density change upon amorphization at certain
+ implantation conditions results in periodically
+ arranged, self-organized, nanometric configurations of
+ the amorphous phase. A simple model explaining the
+ phenomenon is introduced and implemented in a
+ Monte-Carlo simulation code. Through simulation
+ conditions for observing lamellar precipitates are
+ specified and additional information about the
+ compositional and structural state during the ordering
+ process is gained.",
}
@Article{zirkelbach2005,
doi = "doi:10.1016/j.commatsci.2004.12.016",
publisher = "ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM,
NETHERLANDS",
+ abstract = "Ion irradiation of materials, which undergo a drastic
+ density change upon amorphization have been shown to
+ exhibit selforganized, nanometric structures of the
+ amorphous phase in the crystalline host lattice. In
+ order to better understand the process a
+ Monte-Carlo-simulation code based on a simple model is
+ developed. In the present work we focus on high-dose
+ carbon implantations into silicon. The simulation is
+ able to reproduce results gained by cross-sectional TEM
+ measurements of high-dose carbon implanted silicon.
+ Necessary conditions can be specified for the
+ self-organization process and information is gained
+ about the compositional and structural state during the
+ ordering process which is difficult to be obtained by
+ experiment.",
}
@Article{zirkelbach09,
keywords = "Nucleation",
keywords = "Defect formation",
keywords = "Molecular dynamics simulations",
+ abstract = "The precipitation process of silicon carbide in
+ heavily carbon doped silicon is not yet fully
+ understood. High resolution transmission electron
+ microscopy observations suggest that in a first step
+ carbon atoms form C-Si dumbbells on regular Si lattice
+ sites which agglomerate into large clusters. In a
+ second step, when the cluster size reaches a radius of
+ a few nm, the high interfacial energy due to the SiC/Si
+ lattice misfit of almost 20\% is overcome and the
+ precipitation occurs. By simulation, details of the
+ precipitation process can be obtained on the atomic
+ level. A recently proposed parametrization of a
+ Tersoff-like bond order potential is used to model the
+ system appropriately. Preliminary results gained by
+ molecular dynamics simulations using this potential are
+ presented.",
}
@Article{zirkelbach10,
month = sep,
doi = "10.1103/PhysRevB.82.094110",
publisher = "American Physical Society",
-}
-
-@Article{zirkelbach11a,
- title = "First principles study of defects in carbon implanted
- silicon",
- journal = "to be published",
- volume = "",
- number = "",
- pages = "",
- year = "2011",
- author = "F. Zirkelbach and B. Stritzker and J. K. N. Lindner
- and W. G. Schmidt and E. Rauls",
-}
-
-@Article{zirkelbach11b,
- title = "...",
- journal = "to be published",
+ abstract = "A comparative theoretical investigation of carbon
+ interstitials in silicon is presented. Calculations
+ using classical potentials are compared to
+ first-principles density-functional theory calculations
+ of the geometries, formation, and activation energies
+ of the carbon dumbbell interstitial, showing the
+ importance of a quantum-mechanical description of this
+ system. In contrast to previous studies, the present
+ first-principles calculations of the interstitial
+ carbon migration path yield an activation energy that
+ excellently matches the experiment. The bond-centered
+ interstitial configuration shows a net magnetization of
+ two electrons, illustrating the need for spin-polarized
+ calculations.",
+}
+
+@Article{zirkelbach11,
+ title = "Combined ab initio and classical potential simulation
+ study on silicon carbide precipitation",
+ journal = "accepted for publication in Phys. Rev. B",
volume = "",
number = "",
pages = "",
year = "2011",
author = "F. Zirkelbach and B. Stritzker and K. Nordlund and J.
K. N. Lindner and W. G. Schmidt and E. Rauls",
+ abstract = "Atomistic simulations on the silicon carbide
+ precipitation in bulk silicon employing both, classical
+ potential and first-principles methods are presented.
+ The calculations aim at a comprehensive, microscopic
+ understanding of the precipitation mechanism in the
+ context of controversial discussions in the literature.
+ For the quantum-mechanical treatment, basic processes
+ assumed in the precipitation process are calculated in
+ feasible systems of small size. The migration mechanism
+ of a carbon \hkl<1 0 0> interstitial and silicon \hkl<1
+ 1 0> self-interstitial in otherwise defect-free silicon
+ are investigated using density functional theory
+ calculations. The influence of a nearby vacancy,
+ another carbon interstitial and a substitutional defect
+ as well as a silicon self-interstitial has been
+ investigated systematically. Interactions of various
+ combinations of defects have been characterized
+ including a couple of selected migration pathways
+ within these configurations. Almost all of the
+ investigated pairs of defects tend to agglomerate
+ allowing for a reduction in strain. The formation of
+ structures involving strong carbon-carbon bonds turns
+ out to be very unlikely. In contrast, substitutional
+ carbon occurs in all probability. A long range capture
+ radius has been observed for pairs of interstitial
+ carbon as well as interstitial carbon and vacancies. A
+ rather small capture radius is predicted for
+ substitutional carbon and silicon self-interstitials.
+ Initial assumptions regarding the precipitation
+ mechanism of silicon carbide in bulk silicon are
+ established and conformability to experimental findings
+ is discussed. Furthermore, results of the accurate
+ first-principles calculations on defects and carbon
+ diffusion in silicon are compared to results of
+ classical potential simulations revealing significant
+ limitations of the latter method. An approach to work
+ around this problem is proposed. Finally, results of
+ the classical potential molecular dynamics simulations
+ of large systems are examined, which reinforce previous
+ assumptions and give further insight into basic
+ processes involved in the silicon carbide transition.",
}
@Article{lindner95,
projects / lectures / latex.git / commitdiff