RADIATE Summer School

Ion and defect distributions: Monte Carlo simulation

Lecture by Wolfhard Möller

Institute of Ion Beam Physics and Materials Research, HZDR, Dresden, Germany

The lecture will describe basic principles and applications of Monte-Carlo computer simulations of ion-solid interaction using the binary collision approximation (BCA).  An overview of available codes will be given. The model limitations and reliability will be critically discussed. Application results will cover ion implantation, point defect formation, surface sputtering and atomic mixing, as obtained from both static and dynamic simulations, in particular using the TRIM (one-dimensional static), TRIDYN (one-dimensional dynamic) and TRI3DYN¹ (three-dimensional dynamic) codes, the latter in particular with recent results for three-dimensional nanostructures.

1 W. Moeller, Nucl Instrum Meth B 322, 23-33, DOI 10.1016/j.nimb.2013.12.027 (2014)

Tailoring material properties by ion implantation

Lecture by Katharina Lorenz

Instituto Superior Técnico, Lisboa, Portugal

Ion beams can be used to tailor materials properties, for example, by the synthesis of new phases, doping, intermixing, nanopatterning or defect engineering. After a short introduction to the wide field of applications of ion beam modification of materials, this lecture will focus on ion implantation in semiconductors. With this technique, electrical, optical or magnetic dopants can be easily incorporated into a semiconductor crystal. But where exactly in the lattice are the implanted ions incorporated? And how does implantation damage – inevitably formed during the bombardment with energetic ions – impair materials and device properties? Interestingly, some answers can be provided by ion-solid interactions themselves. In particular, we will discuss the measurement of defect profiles and of the lattice site of the implanted ions by Rutherford Backscattering Spectrometry/ion channelling.

Empirical modelling of ion-beam induced damage formation

Lecture by Elke Wendler

Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Germany

This lecture gives an overview of empirical models for describing ion-irradiation-induced defect production and accumulation, and amorphisation. Model calculations illustrate the effect of parameters occurring in the models presented. Various models that represent similar processes are compared with each other. The use of such empirical models may help in understanding of the physical processes during ion irradiation of materials. Further, when a sufficient number of data is available, the obtained model parameters can be analysed on the base of the primary energy deposited by the implanted ions to the atoms of the respective material. This could be used for predicting the damage to be expected for chosen implantation conditions. However, we will also advise you of misinterpretation in the value of such model calculations, because the formulae are built according to possible mechanisms which we guess from our experimental data.

Optical waveguide engineering by ion beams

Lecture by José Olivares^1,2

¹ Instituto de Optica, Consejo Superior de Investigaciones Científicas (IO, CSIC), Madrid, Spain

² Centro de Microanálisis de Materiales, Universidad Autónoma de Madrid (CMAM, UAM), Madrid, Spain

ORCID: 0000-0003-1775-9040; Research ID:  L-3432-2014

Optical waveguides are key elements of many photonic devices, which in turn are essential for the advance of the information society. In addition they can be combined with other singular useful structures like for example nanoparticles with plasmonic properties. Ion irradiation provides a general and flexible method to fabricate or further tune optical waveguides, showing several advantages over the alternative techniques. Initially, optical devices are manufactured using low-energy light ions (H and He at a few MeV), taking advantage of the effects caused by nuclear damage. Later on, the use of the electronic excitation provided by high energy heavy ions (or swift heavy ions for E > 1 MeV/amu) has been developed, allowing to produce novel micro- and nanostructures that make possible to achieve higher optical confinement as needed for example for optical microrings, or nanopore structures.

Swift Heavy Ion irradiation of materials 

Lecture by Miguel C. Sequeira

Instituto Superior Técnico, Lisboa, Portugal

In this lecture, we will address the interaction of Swift Heavy Ions with materials. We will start by looking at the characteristics of this class of strongly ionising radiation. Its differences from other types of radiation, its origins, its effects and its technological importance will be discussed. Afterwards, we will examine the interaction dynamics leading to the observed effects, first from a thermodynamics perspective and latter using atomistic simulations. Special focus will be given to the interaction with semiconductors, namely with group-III nitrides, due to their widespread applications.