Among the many phenomena revealed and provided by nanoscience, the functionalization of a surface by nanopatterning certainly holds promise for a large number of attractive applications. A prominent example is the deposition of self-assembled monolayers by microcontact printing in order to control wettability, adhesion, friction, and wear. [1,2] In this context, the well-known lotus effect should be mentioned. This effect is based on a strong reduction of the adhesion of water droplets by nanopatterning a surface with, for example, dense arrays of statistically distributed nanopillars. [3,4] A further application of such nanopillars is their use as effective electron field emitters, as has been demonstrated for Si, [5,6] a material which is also at the focus of the present work, or, more recently, for diamond. [7] Moreover, highly ordered arrays of nanopillars are extremely helpful for the characterization of individual emitters by scanning tunneling microscopy (STM) or scanning tunneling spectroscopy (STS).For an inverted pattern of nanopillars, that is, ordered arrays of cylindrical nanopores with a high aspect ratio, a similar wealth of possible applications can be thought of. For instance, they can serve as contact holes in semiconductors. According to the present semiconductor technology roadmap, they should exhibit diameters well below 80 nm for the "65 nm node generation".[8] Similarly, applications in nanooptics appear attractive; nanopores based on colloidal masks were fabricated into Si with a diameter of 60 nm. [9] Smaller diameters of the order of 30 nm should be obtainable by nanomachining a poly(methyl methacrylate) PMMA resist with an atomic force microscope and subsequent metal-coating and lift-off, thereby accepting the disadvantage of a nonparallel process. [10] Note that the recently developed technique of controlling the diameter of nanopores in ultrathin Si/SiO 2 membranes by the electron beam of a transmission electron microscope is still a nonparallel procedure.[11] Another approach to preparing nanoholes in Si is based on self-organized porous alumina masks in combination with anisotropic Cl 2 reactiveion etching (RIE). [12] In this way, holes with diameters > 13 nm and an aspect ratio of 3 could be obtained. Similar diameters are obtained by a recently reported technique based on the self-organization of inverse spherical micelles formed from diblock copolymers dissolved in an apolar solvent, such as toluene, and selectively loaded in the micellar core with a metal salt, such as HAuCl 4 .[13-16] By dip-coating such solutions onto practically any sufficiently flat substrate, hexagonally ordered arrays of Au nanodots can be prepared by an ashing process.[17] They can be used as nanomasks in a subsequent anisotropic etching step, resulting in corresponding arrays of nanopillars. In this way, hexagonally ordered pillars with a diameter of 14 nm and an aspect ratio of 5 were obtained in Si. This micellar preparation technique offers a number of impressive advantages, such as the control of the...

A nanolithographic process is introduced based on the self-organization of gold salt loaded inverse micelles formed by poly(styrene)-block-poly(2-vinylpyridine) di-block-copolymers in toluene. The developed procedure allows the fabrication of hexagonally arranged cylindrical nanoholes (diameters ≥20 nm, aspect ratios ∼7) in crystalline as well as in amorphous Si. In the latter case, applying the concept to amorphous Si layers evaporated onto any substrate results in nanomasks allowing the transfer of the hole pattern into the substrate.

We present a method for directly imaging the undisturbed near field of a particle resting on a surface. A comparison with numerical computations shows good agreement with the results of our experiments. These results have important consequences for laser-assisted particle removal where field enhancement may cause local surface damage and is one of the physical key processes in this cleaning method. On the other hand, the application of near fields at particles allows structuring of surfaces with structure dimensions in the order of 100 nm and even below.

Optical problems, related to the particle on the surface, i.e. optical resonance and near-field effects in laser cleaning are discussed. It is shown that the small transparent particle with size by the order of the wavelength may work as a lens in the near-field region. This permits to focus laser radiation into the area with the sizes, smaller than the radiation wavelength. It leads to 3D effects in surface heating and thermal deformation, which influences the mechanisms of the particle removal.

SummaryFor many applications it is desirable to have nanoparticles positioned on top of a given substrate well separated from each other and arranged in arrays of a certain geometry. For this purpose, a method is introduced combining the bottom-up self-organization of precursor-loaded micelles providing Au nanoparticles (NPs), with top-down electron-beam lithography. As an example, 13 nm Au NPs are arranged in a square array with interparticle distances >1 µm on top of Si substrates. By using these NPs as masks for a subsequent reactive ion etching, the square pattern is transferred into Si as a corresponding array of nanopillars.