Metal nanoparticle film-based room temperature Coulomb transistor.

Single-electron transistors would represent an approach to developing less power-consuming microelectronic devices if room temperature operation and industry-compatible fabrication were possible. We present a concept based on stripes of small, self-assembled, colloidal, metal nanoparticles on a back-gate device architecture, which leads to well-defined and well-controllable transistor characteristics. This Coulomb transistor has three main advantages.

Coulomb blockade based field-effect transistors exploiting stripe-shaped channel geometries of self-assembled metal nanoparticles.

Metallic nanoparticles offer possibilities to build basic electric devices with new functionality and improved performance. Due to the small volume and the resulting low self-capacitance, each single nanoparticle exhibits a high charging energy. Thus, a Coulomb-energy gap emerges during transport experiments that can be shifted by electric fields, allowing for charge transport whenever energy levels of neighboring particles match.

Group 8 metallocenes as bulky functional groups in glucopyranosides.

The functionalization of methyl D-glucopyranosides at positions 4 and 6 with bulky moieties was carried out by using ferrocenyl and ruthenocenyl substituents. The synthesis succeeded by reaction of the methyl D-glucopyranosides with the corresponding metallocene monocarbaldehyde dimethyl acetal catalysed by iodine in acetonitrile. The resulting compounds methyl 4,6-O-(metallocenylmethylidene)-α-D-glucopyranoside (M=Fe (1) and M=Ru (3)) and methyl 4,6-O-(metallocenylmethylidene)-β-D-glucopyranoside (M=Fe (2) and M=Ru (4)) were characterized by (1)H and (13)C NMR spectroscopy, by crystal structure determination as well as elemental analysis.

Adhesion and size dependent friction anisotropy in boron nitride nanotubes.

The frictional properties of individual multiwalled boron nitride nanotubes (BN-NTs) synthesized by chemical vapour deposition (CVD) and deposited on a silicon substrate are investigated using an atomic force microscope tip sliding along (longitudinal sliding) and across (transverse sliding) the tube's principal axis. Because of the tube's transverse deformations during the tip sliding, a larger friction coefficient is found for the transverse sliding as compared to the longitudinal sliding. Here, we show that the friction anisotropy in BN-NTs, defined as the ratio between transverse and longitudinal friction forces per unit area, increases with the nanotube-substrate contact area, estimated to be proportional to (L(NT)R(NT))(1/2), where L(NT) and R(NT) are the length and the radius of the nanotube, respectively.