Bromine functionalized molecular adlayers on hydrogen passivated silicon surfaces

Well controlled and characterized organic functionalization is a necessary precondition for the fabrication of many silicon-based molecular electronic and sensing devices. Of particular interest are organic modifications that incorporate bromine since heavy atoms can be directly interrogated by X-ray radiation and organohalides provide synthetic handles through which more chemically elaborate structures may be covalently bound to silicon. This paper specifically considers the functionalization of hydrogen passivated silicon surfaces with 4-bromostyrene. X-ray photoelectron spectroscopy confirms the reaction of 4-bromostyrene with monohydride Si(1 0 0) and Si(1 1 1) surfaces such that the bromine moiety is preserved on top of the organic adlayer. In addition, ultra-high vacuum scanning tunneling microscopy reveals that the 4-bromostyrene molecules assemble into one-dimensional nanostructures on the Si(1 0 0)-2 × 1:H surface. Overall, these experimental results demonstrate that styrene derivatives serve as effective organic molecules for the chemical functionalization of hydrogen passivated silicon surfaces.