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O: Fachverband Oberflächenphysik

O 16: Organic, Polymeric, and Biomolecular Films I

O 16.12: Vortrag

Montag, 26. März 2007, 17:00–17:15, H42

Electrospray Ion Beam Vacuum Deposition of Organic Molecules and Inorganic Clusters — •Stephan Rauschenbach, Nicha Thontasen, Nicola Malinowski, and Klaus Kern — Max-Planck-Institut for Solid State Research, Nanoscale Science Department, Heisenbergstr. 1, 70569 Stuttgart

Electrospray Ionization (ESI) is widely used as ionization technique for mass spectrometric applications in biology and organic chemistry, because of the unique destruction free ionization of even large biological molecules from solution.

In our experiment ESI is used to bring nonvolatile compounds into gas phase. An apparatus employing differential pumping, ion optical devices and time-of-flight mass analysis (TOF-MS) was constructed in order to deposit ions created by ESI under very controlled conditions on solid surface in ultra-high-vacuum (UHV). The samples can be analyzed ex-situ or in-situ by a variable temperature UHV-STM/AFM.

The technique is demonstrated by two examples: the deposition of clusters and the creation of monolayer films of organic salts. Various types of large inorganic clusters could be ionized and deposited. The layers of organic salts on the other hand were formed from small cluster ions of the type A⁺(AB)_n. AFM images show single or double molecular layers depending on the substrate. On the surface the molecules can diffuse and align along substrate features like step edges.

S. Rauschenbach, F. Stadler, E. Lunedei, N. Malinowski, S. Koltsov, G. Costantini, K. Kern, Electrospray Ion Beam Depostion of Clusters and Biomolecules, Small 4 (2006)