Supramolecular Self-Assemblies as High-Density Data-Storage Media
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0961-O16-04
Supramolecular Self-Assemblies as High-Density Data-Storage Media Nikolai Wintjes1, Markus Wahl1, Andreas Kiebele1, Meike Stohr1, Silvia Schintke1, Hannes Spillmann1, Hans-Joachim Güntherodt1, Lutz Gade2, D. Bonifazi3, F. Cheng4, F. Diederich4, and Thomas Jung5 1 Department of Physics, University of Basel, Klingelbergstr. 82, Basel, 4056, Switzerland 2 Inorganic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, Heidelberg, 69120, Germany 3 Chemistry, University of Trieste, Trieste, Italy 4 Organic Chemistry, ETH-Zürich, Hoenggerberg HCI, Zürich, 8093, Switzerland 5 Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, Laboratory for Microand Nanotechnology, Villigen, 5232, Switzerland The affordable and reproducible creation of nanoscale functional material layers is a key desire towards the progressing miniaturization of devices and the continuous increase of data storage densities. While top-down structuring costs are exploding, the self-assembly [1] of dedicated building blocks in functional molecular layers provides an alternative to produce structures in the few nanometer range. Here several different approaches to produce well defined funtional behaviour by ‘dry’ – water free self assembly are introduced and discussed in the context of data-storage. The dedicated assembly of two dimensional molecular layers on prepatterned surfaces provides the basis for structural transitions involving only some hundred molecules. Such a transition from a mobile into an ordered phase of dipole bearing molecules in vacancy islands can be reversibly triggered by an electric field applied e.g. by the tip of a Scanning Tunneling Microscope (Figure 1A). (ist übrigens nicht als solche erkennbar, da A, B, C, D fehlen, aber es in 1B) a, b, c, d gibt) [2] Although the control over the transition is exploitable in the context of patterned media, a clear disadvantage derives from the fact that the vacancy islands are randomly distributed on the surface. This can be circumvented by using self assembly in balance of long range electrostatic inter-molecular interactions with adsorbate-adsorbent interactions in the contact regime to provide clearly confined self organised layers with a characteristic dimension of three nanometers as shown in Figure 1B). (Ja, aber wie willst du das als Speicher-Medium nutzen, das steht hier nicht.) [3] Another crucial requirement to match self-assembled functional devices with top-down manufactured methods for addressing and operation, is to increase the range of ordering. This is achieved by using larger molecular entities that exhibit specially designed conformational flexure properties, [4] which lead to a site-blocking mechanism in the second layer. By this, when evaporating a second type of molecules onto the first layer, they self-assemble into a highly regular and stable second layer, which shows long-range ordering (Figure 1C). [5] To even further increase the characteristic dimension of the functional structures, a hierarchical two step approach can be used. The in
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