Reaction of Hydroquinone and p-Benzoquinone with the Ge(100)-2 × 1 Surface

The adsorption behavior of two bifunctional molecules, hydroquinone (HO–C 6 H 4 –OH) and p -benzoquinone (O═C 6 H 4 ═O), on the germanium (100) surface is studied. A combination of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy experiments together with density functional theory calculations were used to identify the products. The distinct functionalities of the reactants result in different reaction pathways, namely, OH dissociation for hydroquinone and cycloaddition for p -benzoquinone. Yet, the major product formed, a dually tethered surface hydroquinoxy group with an aromatic ring (−OC 6 H 4 O–), is the same for both molecules. Dual dissociation of hydroquinone was highly selective in stereochemical configuration. Minor singly tethered products are also found for both precursors. The results suggest that selective attachment of aromatic groups on semiconductor surfaces can be achieved by choosing proper functionalities of the reactants.