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A novel coarse approach mechanism for a scanning tunneling microscope (STM) is described. Any approach mechanism, which brings a tip close to the sample, suffers from dry frictional force, which makes positioning of the tip over the sample rather difficult. In this unique design, we have reduced the friction to a minimum by oscillating the normal force on the sliding sapphire surfaces. This technique allows us to precisely position the tip over the sample after traveling a distance greater than 100 μm while maintaining a compact STM design. This technique of reducing friction is also very useful in an automatic inertial approach mechanism (or “stick–slip” motor), where the motion often becomes clamped due to excessive friction. We believe that this technique will be extremely useful for applications where high precision positioning is required.

An inert, precursor free, argon jet is used to control the growth rate of electron beam induced deposition. Adjustment of the jet kinetic energy/inlet temperature can selectively increase surface diffusion to greatly enhance the deposition rate or deplete the surface precursor due to impact-stimulated desorption to minimize the deposition or completely clean the surface. Physical mechanisms for this process are described. While the electron beam is also observed to generate plasma upon interaction with an argon jet, our results indicate that plasma does not substantially contribute to the enhanced deposition rate.

We report the use of thermochemical nanolithography to convert a precursor polymer film to poly(p-phenylene vinylene) with sub-100 nm spatial resolution, in ambient conditions. The local thermochemical conversion is verified by Raman spectroscopy, fluorescence imaging, and atomic force microscopy. This convenient direct writing of conjugated polymer nanostructures could be desirable for the design and fabrication of future nanoelectronic, nanophotonic, and biosensing devices.

The effects of film composition and postnitridation annealing on band gap and valence band offset were examined in nitrided Hf-silicate films prepared using direct plasma nitridation. Regardless of the composition of Hf-silicate films, the band gap characteristics were similar after direct plasma nitridation (4.5±0.1eV) and postnitridation annealing (5.6±0.1eV). The decrease in band gap after direct plasma nitridation was caused by the formation of Si–N and Hf–N bonds, while the recovery of band gap by postnitridation annealing was influenced by the dissociation of unstable Hf–N bonds. The difference in valence band offset was strongly related to the chemical states of Si–N bonds.