Architecturing covalently bonded organic bilayers on the Si(111)-(7 × 7) surface via in situ photoinduced reaction

Abstract

Controlled formation of covalently bonded N-benzylideneaniline-like molecular layers has been achieved by photoinduced reaction of benzonitrile molecules physisorbed on the 4-bromostyrene modified Si(111)-(7 × 7) surface. The photoinduced reaction results in the C-Br bond cleavage and produces a radical site which concurrently reacts with the C - N cyano group of the physisorbed benzonitrile molecule above to form the -C-N=C- covalent linkage. X-ray photoelectron spectroscopy (XPS) and high-resolution electron energy loss spctroscopy (HREELS) experiments together with density functional theory (DFT) calculations confirm the formation of covalently bonded N-benzylideneaniline-like molecular layers on the silicon surface. The formation of this secondary molecular layer by photoinduced reaction may provide a direct pathway for further organic synthesis and fabrication of organic multilayers on semiconductor surfaces in a well-controlled enviornment. © 2012 American Chemical Society.