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Nanotubular structures in the B-C-N ceramic system represent an intriguing alternative to conventional carbon nanotubes.Because of the ability to widely vary the chemical composition of nanotubes within the B-C-N ternary phase diagram and to change the stacking of C-rich or BN-rich tubular shells in multiwalled structures, a wide horizon opens up for tuning nanostructure electrical properties.Pure carbon nanotubes are metals or narrow-bandgap semiconductors, depending on the helicity and diameter, whereas those of BN are insulators with a ∼5.0eV gap independent of these parameters.Thus, the relative B/C/N ratios and/or BN-rich and C-rich domain spatial arrangements, rather than tube helicity and diameter, are assumed to primarily determine the B-C-N nanotube electrical response.This characteristic is highly valuable for nanotechnology:while tube diameter and helicity are currently difficult to control, continuous doping of C with BN, or vice versa, proceeds relatively easily due to the isostructural nature of layered C and BN materials.In this article, recent progress in the synthesis, microscopic analysis, and electrical property measurements of a variety of compound nanotubes in the ceramic B-C-N system is documented and discussed.

methanol produced from the hydrolysis of the TMOS was slowly removed using a diaphragm vacuum pump (DIVAC 1.2 L) connected to a rotary evaporator at ambient temperature to avoid the destruction of the liquid-crystalline order [20,22]. Within about 5 min, the resulting viscous liquid changed to a translucent, gel-like substance and acquired the desired shape and size of the reaction vessel (Fig. 1). The translucent glassy monoliths were collected and dried at 40 C for 16 h. The surfactant and the incorporated alkanes were removed by calcination at 450 C (3 h under nitrogen and then 14 h under oxygen).XRD patterns were measured using a MXP 18 diffractometer (Mac Science Co. Ltd.) with Cu Ka radiation. The N 2 isothermal data were collected with a Shimadzu ASAP 2020 surface area analyzer. All samples were outgassed at 300 C for 8 h before the N 2 adsorption analyses. The TEM micrographs were obtained with a JEOL JEM-2000 FXII Apparatus operating at an acceleration voltage of 200 kV. SEM micrographs were also obtained with a Hitachi S-800 SEM operated at 7 kV.

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Molecular fluorescence from the surface of ZnTBP porphyrin (ZnTBPP) molecular layers on Cu(100) is induced with nanoprobe excitation in the tunnelling regime. The observed well-defined molecular fluorescence is a perfect match with the standard photoluminescence data of ZnTBPP molecules. The decoupling of the electronic state of the top layer ZnTBPP is controlled by the thickness of the molecular layers. The excitation mechanism of molecular luminescence may be attributed to the hot electron injection into the molecules in proximity to the tip apex of a scanning tunnelling microscope. This approach features simplicity, bipolar operation and good reproducibility. The research provides a new way for the integration of molecular fluorescence with a nanoprobe and the development of a nanoscale molecular light source.

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