Growth Mechanism Of Organic Nanocrystals On Passivated Semiconductor Surfaces

We describe the formation of organic nanocrystals from 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) molecules on the inert H-Si(100) surface. Scanning tunneling microscopy reveals specific orientations and morphologies for the nanocrystals. By determining the coincidences between the surface and interfacial molecular lattices, we show that the molecule-surface interaction governs the growth process. Based on this coincidence model, we predict the shape of PTCDA nanocrystals on other passivated semiconductor surfaces.