  Accurate deposition of nanoparticles at defined positions on a substrate is
still a challenging task, because it requires simultaneously stable long-range
transport and attraction to the target site and precise short-range orientation
and deposition. Here we present a method based on geometry-induced energy
landscapes in a nanofluidic slit for particle manipulation: Brownian motors or
electro-osmotic flows are used for particle delivery to the target area. At the
target site, electrostatic trapping localizes and orients the particles.
Finally, reducing the gap distance of the slit leads sequentially to a focusing
of the particle position and a jump into adhesive contact by several
nanometers. For 60 nm gold spheres, we obtain a placement accuracy of 8 nm. The
versatility of the method is demonstrated further by a stacked assembly of
nanorods and the directed deposition of InAs nanowires.
