ABSTRACT
The critical dimension of semiconductor devices is approaching the single-nm regime, and a variety of practical devices of this scale are targeted for production. Planar structures of nano-devices are still the center of fabrication techniques, which limit further integration of devices into a chip. Extension into 3D space is a promising strategy for future; however, the surface interaction in 3D nanospace make it hard to integrate nanostructures with ultrahigh aspect ratios. Here we report a unique technique using high-energy charged particles to produce free-standing 1D organic nanostructures with high aspect ratios over 100 and controlled number density. Along the straight trajectory of particles penetrating the films of various sublimable organic molecules, 1D nanowires were formed with approximately 10~15 nm thickness and controlled length. An all-dry process was developed to isolate the nanowires, and planar or coaxial heterojunction structures were built into the nanowires. Electrical and structural functions of the developed standing nanowire arrays were investigated, demonstrating the potential of the present ultrathin organic nanowire systems.
ABSTRACT
X-ray absorption spectroscopy measurements were performed for the C K-edge of Pt nanoparticles on Ar+-irradiated carbon supports in order to elucidate the origin of improved catalyst performance after the introduction of vacancies into the carbon support. We observed a change in the electronic structure at the interface between the Pt nanoparticles and the carbon support after vacancy introduction, which is in good agreement with theoretical results. The results indicated that vacancy introduction resulted in a drastic change in the Pt-C interactions, which likely affected the d-band center of the Pt nanoparticles and led to the enhancement of the oxygen reduction reaction in catalysts.
