Since the first report of Si-C bound organic monolayers on oxide-free Si almost two decades ago, a substantial amount of research has focused on studying the fundamental mechanical and electronic properties of these Si/molecule surfaces and interfaces. This feature article covers three closely related topics, including recent advances in achieving high-density organic monolayers (i.e., atomic coverage >55%) on oxide-free Si(111) substrates, an overview of progress in the fundamental understanding of the energetics and electronic properties of hybrid Si/molecule systems, and a brief summary of recent examples of subsequent functionalization on these high-density monolayers, which can significantly expand the range of applicability. Taken together, these topics provide an overview of the present status of this active area of research.

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Gold nanoparticles were synthesized by a hot-wire generator at atmospheric pressure using a gold-platinum composite wire. At low gas flow velocities the nanoparticles were found to be agglomerates of partially sintered primary particles. By reducing the tube size via the insertion of a nozzle with a throat diameter of 3 mm, the hot-wire generator was found to produce small (<10 nm diameter) crystalline gold particles. Elemental and x-ray photoelectron spectroscopy analysis of the particles showed that they were composed of gold with no platinum impurity. Charging analysis of the "as-produced" nanoparticles showed that fewer than 10% of the particles were charged, but the charge fraction increased as the applied power increased, as did the ratio of negatively-topositively-charged particles.