Conferencia Leo Gross (IBM Research Labs, Zurich)

Individual Molecules Investigated by Scanning Probe Microscopy with Atomically Functionalized Tips
L. Gross, F. Mohn, B. Schuler, N. Moll, G. Meyer
IBM Research - Zurich, 8803 Rüschlikon, Switzerland

Single organic molecules adsorbed on ultrathin insulating films were investigated using scanning tunnelling microscopy (STM), noncontact atomic force microscopy (NC-AFM), and Kelvin probe force microscopy (KPFM). With all of these techniques submolecular resolution was obtained due to tip functionalization by atomic manipulation. The techniques yield complementary information regarding the molecular structural and electronic properties.

Using NC-AFM with CO functionalized tips, atomic resolution on molecules was demonstrated [1]. Moreover, different bond orders of individual carbon-carbon bonds in polycyclic aromatic hydrocarbons and fullerenes were distinguished [2]. Using KPFM information about the distribution of charges within molecules was gained [3].

Recently, we investigated other tip functionalizations for AFM, i.e., Cl, Br, Xe, Kr, and NO [4]. The prospects to use high resolution AFM for molecular structure identification [5] or adsorption geometry determination will be discussed.

[1] L. Gross, F. Mohn, N. Moll, P. Liljeroth, G. Meyer, Science 325, 1110 (2009)
[2] L. Gross, F. Mohn, N. Moll, B. Schuler, A. Criado, E. Guitián, D. Peña, A. Gourdon, G. Meyer, Science 337, 1326 (2012)
[3] F. Mohn, L. Gross, N. Moll, G. Meyer Nature Nanotechnol. 7, 227 (2012)
[4] F. Mohn, B. Schuler, L. Gross, G. Meyer, Appl. Phys. Lett. in print (2013)
[5] L. Gross, F. Mohn, N. Moll, G. Meyer, R. Ebel, W. M. Abdel-Mageed, M. Jaspars, Nature Chem. 2, 821 (2010)

Figure: Different scanning probe microscopy modes (STM, AFM and KPFM) using functionalized tips demonstrated with atomic resolution on a single naphthalocyanine molecule adsorbed on a double layer NaCl on Cu(111