Hydrogermylation of alkenes and alkynes on hydride-terminated Ge(100) surfaces

Covalently bonded organic monolayers on semiconductor surfaces are potentia lly important for the fabrication of novel electronic devices and sensors. In contrast to the recent interest in and development of methods for monola yer formation on silicon surfaces, only one wet chemical route has been pre viously published for germanium surfaces. We present novel strategies to pr epare organic monolayers on hydride-terminated Ge(100) surfaces utilizing t he available Ge-H bonds as chemical handles. The new hydride-terminated Ge( 100) surface was prepared by utilizing an efficient preparation method invo lving soaking in an aqueous 10% HF solution. Lewis acid mediated hydrogermy lation of alkynes and alkenes on the hydride-terminated Ge(100) surfaces re sults in alkenyl and alkyl surfaces, respectively, bound through Ge-C bonds . Thermal treatment of hydride-terminated Ge surface with neat alkenes and alkynes, or solutions in mesitylene, also results in similar organic monola yers. Finally, these two approaches were contrasted with UV photoinduced hy drogermylation of alkenes. The resulting organic monolayers were characteri zed by infrared spectroscopy (ATR-FTIR), stability studies, and contact ang le measurements.