Sub 20 nm Short Channel Carbon Nanotube Transistors

Carbon nanotube field-effect transistors with sub 20 nm long channels and on/off current ratios of > 1000000 are demonstrated. Individual single-walled carbon nanotubes with diameters ranging from 0.7 nm to 1.1 nm grown from structured catalytic islands using chemical vapor deposition at 700 degree Celsius form the channels. Electron beam lithography and a combination of HSQ, calix[6]arene and PMMA e-beam resists were used to structure the short channels and source and drain regions. The nanotube transistors display on-currents in excess of 15 microA for drain-source biases of only 0.4 Volt.Comment: Nano Letters in pres

Bias Dependence and Electrical Breakdown of Small Diameter Single-Walled Carbon Nanotubes

The electronic breakdown and the bias dependence of the conductance have been investigated for a large number of catalytic chemical vapor deposition (CCVD) grown single-walled carbon nanotubes (SWCNTs) with very small diameters. The convenient fabrication of thousands of properly contacted SWCNTs was possible by growth on electrode structures and subsequent electroless palladium deposition. Almost all of the measured SWCNTs showed at least weak gate dependence at room temperature. Large differences in the conductance and breakdown behavior have been found for "normal" semiconducting SWCNTs and small band-gap semiconducting (SGS) SWCNTs.Comment: submitted to Journal of Applied Physic

Leuchtendes Silizium - Untersuchungen zum Potential fuer industrielle Anwendungen Schlussbericht

The project was proposed after the discovery of visible photoluminescence from porous silicon (PS) at roomtemperature in order to investigate the potential of PS for industrial applications. It was found that the luminescence can be understood in the frame of a Quantum-size-model. The low conductivity of PS is a consequence of its minute sponge-like structure. The longtime stability of the structure can be increased by partial oxidation. Contacts made by conductive polymers, as well as poly-silicon, were investigated. The low intensity of the electroluminescence, the contact problems and the high carrier lifetimes are the major drawbacks of the material. In the light of these findings device applications of the material seem to be unlikely in the near future. (orig.)SIGLEAvailable from TIB Hannover: DtF QN1(42,41) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman