Here we report the solution-liquid-solid (SLS) synthesis of silicon (Si) nanowires. Nanowires are grown by trisilane (Si3H8) decomposition in a high boiling solvent, octacosane (C28H58) or squalane (C30H62), in the presence of either Au or Bi nanocrystals. To our knowledge, this is the first report of a colloidal synthetic route carried out in a solvent at atmospheric pressure that provides crystalline Si nanowires in large quantities.

Hexagonally close-packed monolayers of FePt nanocrystals were deposited on silicon substrates by Langmuir−Blodgett, Langmuir−Schäfer, or spin-coating techniques and characterized by scanning electron microscopy (SEM) and grazing incidence small-angle X-ray scattering (GISAXS). The extent of order in each nanocrystal film is quantified based on the GISAXS data and compared. The LB technique provided the most ordered superlattice films.

The colloidal synthesis of crystalline silicon (Si) nanorods with diameters of 5 to 10 nm and lengths of 15 to 75 nm is demonstrated. Trisilane was decomposed in a hot solvent in the presence of dodecylamine and gold (Au) nanocrystals. Nanorods form by Au-seeded solution-liquid-solid growth with dodecylamine serving as capping ligands that stabilize the nanorod dispersion. Post-synthesis etching of the Au seeds from the nanorod tips is also demonstrated.

Hexagonally ordered close-packed monolayers of sterically stabilized FePt nanocrystals were deposited on substrates using the Langmuir-Blodgett technique. Monolayers of nanocrystals were also stacked by sequential Langmuir-Blodgett transfer. The structures of the nanocrystal monolayers and multilayer stacks were examined with scanning electron microscopy (SEM) and grazing-incidence small-angle scattering (GISAXS). An analytical model derived from the quasikinematic approximation provides a convenient description of the GISAXS data of the stacked layers. The transferred monolayers showed good in-plane hexagonal order, even for trilayers. Bilayers exhibited spatial registry with the top layer positioned above the 3-fold coordinated sites of the bottom layer. Trilayers, on the other hand, exhibited significant disorder.