Field test of quantum key distribution in the Tokyo QKD Network

A novel secure communication network with quantum key distribution in a metropolitan area is reported. Different QKD schemes are integrated to demonstrate secure TV conferencing over a distance of 45km, stable long-term operation, and application to secure mobile phones.Comment: 21 pages, 19 figure

ATOM-PROBE STUDY OF POLYPYRROLE : DISTRIBUTION OF DOPANTS AND OXYGEN

The atom-probe analysis of BF4--doped polypyrrole (PP) revealed that the fresh PP layer polymerized electrochemically on a Pt tip has two regions : B-rich region and B-free region at the initial stage of oxidation. The thickness of these regions are found to be a few tens angstroms. The observed non-uniform B distribution can be attributed to the intrinsic profile of the fresh PP layer. The exclusion of boron from the fully oxidized PP layer may indicate the repulsive B-O interaction

Amorphous carbon for use in thin film transistors

Tetrahedrally bonded amorphous carbon (ta-C) is a new type of semiconducting thin film material. It can be produced at room temperature using the Filtered Cathodic Vacuum Arc technique. The as-grown undoped ta-C is p-type in nature but it can be n-doped by the addition of nitrogen during deposition. This paper will describe thin film transistor design and fabrication using ta-C as the active channel layer

A carbon based bottom gate thin film transistor

This paper describes the fabrication and characterization of a carbon based, bottom gate, thin film transistor (TFT). The active layer is formed from highly sp2 bonded nitrogenated amorphous carbon (a-C:N) which is deposited at room temperature using a filtered cathodic vacuum arc technique. The TFT shows p-channel operation. The device exhibits a threshold voltage of 15 V and a field effect mobility of 10-4 cm2 V-1 s-1 . The valence band tail of a-C:N is observed to be much shallower than that of a-Si:H, but does not appear to severely impede the shift of the Fermi level. This may indicate that a significant proportion of the a-C tail states can still contribute to conduction