Towards π-wires on a semiconductor surface: Benzyne on Si(001).

Towards the goal of covalently bound molecular wires on silicon, the adsorption of benzyne on Si(001) was studied by means of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and density functional calculations (DFT). The benzyne molecule is found to adsorb preferentially via the strained triple bond on one dimer of the Si(001) surface which results in an intact π system covalently bound to the surface. With increasing coverage, the molecules primarily adsorb along the dimer rows; on stepped surfaces, these molecular wires are all oriented in the same direction.