  The adsorption of two kinds of porphyrin (Cu-TBPP) and perylene (PTCDA)
derived organic molecules deposited on KBr and Al2O3 surfaces has been studied
by non-contact force microscopy in ultra-high vacuum, our goal being the
assembly of ordered molecular arrangements on insulating surfaces at room
temperature. On a Cu(100) surface, well ordered islands of Cu-TBPP molecules
were successfully imaged. On KBr and Al2O3 surfaces, it was found that the same
molecules aggregate in small clusters at step edges, rather than forming
ordered monolayers. First measurements with PTCDA on KBr show that
nanometre-scale rectangular pits in the surface can act as traps to confine
small molecular assemblies.
