Organic Molecular Films

Cu-TBPP and PTCDA molecules on insulating surfaces studied by ultra-high-vacuum non-contact AFM

“…the application of voltage pulses, turns out to be difficult owing to interference with the maintenance of the tip oscillation, and is not feasible on insulating surfaces anyway. Another difficulty in nc-AFM on heterogenous surfaces is the variation of long-range forces between substrate or molecular islands on the one hand, and the tip on the other hand, for example due to work function variations [5,15]. Feedback parameters suitable for highresolution imaging on the substrate may be inadequate for the molecules.…”

“…As more complex systems of structured molecular monolayers and metallic wiring on insulating substrates are developed, the development of scanning force microscopy (SFM) into a tool with similar resolution on molecular films to STM is highly desirable. Progress in dynamic force microscopy, in particular non-destructive imaging, usually referred to as non-contact AFM (nc-AFM), led to several studies where molecular resolution could be obtained based on the tip-sample interaction for distance control (see [5] and references therein). Beyond imaging, force microscopy experiments can also determine forces involved in the manipulation of molecules [6].…”

Advances in atomic force microscopy

“…35). Other semiconductors (Sugawara et al, 1995;Morita and Sugawara, 2002), more ionic crystals Barth, 1999, 2002;Bennewitz, Bammerlin, and Meyer, 2002), metal oxides (Fukui et al, 1997;Raza et al, 1999;Barth and Reichling, 2002;Fukui and Iwasawa, 2002;Hosoi et al, 2002;Pang and Thornton, 2002), metals (Loppacher et al, 1998;Minobe et al, 1999), organic monolayers (Gotsmann et al, 1998;Yamada, 2002), adsorbed molecules (Sasahara and Onishi, 2002;Sugawara, 2002), and even a film of xenon physisorbed on graphite (Allers et al, 1998;see Fig. 36) were imaged with atomic resolution.…”