Nanostructures formed on surfaces due to the impact of slow highly charged ions

01.01.2010 - 30.12.2013
Scholarship
The idea of modifying surfaces on the nanoscale in a defined and reproducible way, for example "writing" on a surface, has captured the interest of researchers for some time. Among the tools for such lithographic surface modification are ion beams. Earlier studies on ion-surface interactions were mainly conducted at relatively high ki- netic energies and low ion charge states. Swift heavy ion (MeV - GeV) irradiation of solid targets has been extensively studied and shown to induce severe structural modfications not only at the surface but also in the bulk. The damage of deeper layers, however, is a major limitation for the use of high-energy ions in nanotechnological applications. Research in the Field of slow (eV - keV) highly charged ions (HCI) and their interaction with surfaces has been fueled by the desire to confine energy deposition to the topmost surface layers and the continuous development in ion source technology and scanning probe microscopy. HCI carry a large amount of potential energy equal to the total ionization energy required for their production. It is now possible to perform experiments where the potential energy of the incident projectiles becomes comparable with or even greatly exceeds their kinetic energy. In such a way, "potential effects" become dominant and any "kinetic effects" play a less important role. Experimental studies under such conditions performed within the group of Prof. Aumayr at TU Wien provided first unambiguous evidence that the potential energy (above a threshold value) of an incident ion alone is sufficient to create a nano-sized protrusion (hillock) on a CaF2 surface [Phys. Rev. Lett. 100 , 237601 (2008)]. From a multitude of irradiated CaF2 samples that have been investigated by means of atomic force microscopy (AFM), the hillock size in dependence of irradiation parameters could be determined. Through modelling calculations and simulations the observed potential energy threshold could be linked to a solid-liquid phase transition. It is the primary aim of the proposed DOC scholarship thesis to carry out similar systematic studies on other promising materials, in order to gain insight into the basic mechanisms of defect creation and to correlate these mechanisms to material properties. The PhD work will be performed in close collaborations with leading European research facilities, which the applicant has already visited and worked with in the course of his diploma thesis.

People

Project leader

Subproject managers

Project personnel

Institute

Grant funds

  • Österr. Akademie der Wissenschaften (National) Austrian Academy of Sciences

Research focus

  • Beyond TUW-research focus: 100%

Keywords

GermanEnglish
hochgeladenen Ionenhighly charged ions
Nanostrukturierungnano structuring
Ion-Oberflächen Wechselwirkungion-surface interaction

External partner

  • Max-Planck-Institut für Kernphysik in Heidelberg
  • GANIL, CIMAP
  • Forschungszentrum Dresden in Rossendorf

Publications