STM study of large organic molecules adsorption on Si(100)-2 × 1

The adsorption of large organic molecules, including tetracene and perylene, on clean Si(100) is followed by scanning tunnelling microscopy (STM) in an ultra high vacuum environment. Different adsorption sites have been observed for these organic molecules. Two types of tetracene adsorption are indicated by filled state images but three types can be distinguished in empty state images. Molecules aligned both along and perpendicular to the silicon dimer rows can be observed. Measurements of the length of this molecule in all configurations indicate that the molecule stays intact during the adsorption process. High resolution of STM images reveal that the perylene molecules bond to the substrate in a vertical orientation and forming packs of perylene aligned perpendicular to the silicon dimmer rows. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)