The research topics of the proposed Christian Doppler Laboratory for Direct-WritE FabricatIon of 3D NanoprobEs aims on radically new concepts in the field of in situ atomic force microscopy enabled by an emerging 3D nano-printing technology.
The research program is centred around Focused Electron Beam Induced Deposition (FEBID) which is an increasingly relevant direct-write technology for flexible, bottom-up synthesis of high-resolution nanostructures, virtually applicable on any substrate material and morphology. While the fundamental understanding of FEBID based fabrication for planar and bulky 3D structures has made tremendous progress in recent years, the direct fabrication of complex free-standing 3D structures is still in its early stages with respect to its controllability, tunability and reliability on the nanoscale. The same holds for the material composition of FEBID materials mostly containing considerable amounts of carbon impurities which reduce or even mask the intended functionalities entirely. In the past, successful approaches have been demonstrated to obtain pure metallic planar (nano)structures, but the transfer of free-standing 3D structures into pure metals remains still challenging as the fundamental processes are not fully understood. Both aspects, true 3D nano-fabrication and successful transfer to pure metal materials, are core competences of FELMI, the lead institution for this CDL. We strongly believe that this represents the ideal basis for further basic research in this field which is indispensably required to leverage this technology into the status of a reliable 3D nano-printing tool for application by our industrial partner GETEC as long term vision within this CDL. In more detail, the research activities will focus on two main aspects:
1) controlled 3D nanofabrication and
2) defined material properties.
The first focus aims at unravelling the fundamentally involved aspects relevant for controlled 3D fabrication taking into account physiochemical processes as well as technical implications of the setup. This will act as input for the simulation-assisted fabrication of complex 3D structures with emphasis on predictability, tunability and repeatability with spatial nanometer resolution. The second focus lies on the chemical transfer into carbon-free materials without disrupting the intended morphology. This is particularly challenging as the transfer goes along with a massive volume loss leading to spatial stress-strain effects which can significantly affect the structural integrity of the 3D nanostructure. To approach this problem finite element simulations will be used in combination with experiments and technical aspects to develop an improved understanding of the chemical transfer process and to finally obtain the intended 3D architectures with an impurity-free character.