Publications by Ralf Thomas Weitz

Separating the impact of oxygen and water on the long-term stability of n-channel perylene diimide thin-film transistors

Klaus Kern, Ralf Thomas Weitz, Hagen Klauk

A detailed understanding for the mechanisms that control degradation of the electrical performance of organic thin-film transistors (TFTs) during exposure to various environments, such as oxygen and humidity, is still developing. This is particularly true ...

Elsevier Science Bv2015

Crystalline Inverted Membranes Grown on Surfaces by Electrospray Ion Beam Deposition in Vacuum

Klaus Kern, Stephan Rauschenbach, Ralf Thomas Weitz, Theresa Lutz, Nicha Thontasen, Gordon Rinke, Giovanni Costantini

Wiley2012

Top-Gate ZnO Nanowire Transistors and Integrated Circuits with Ultrathin Self-Assembled Monolayer Gate Dielectric

Klaus Kern, Ralf Thomas Weitz, Frederik Sebastian Ante, Hagen Klauk

A novel approach for the fabrication of transistors and circuits based on individual single-crystalline ZnO nanowires synthesized by a low-temperature hydrothermal method is reported. The gate dielectric of these transistors is a self-assembled monolayer t ...

American Chemical Society (ACS)2011

Logic circuits based on individual semiconducting and metallic carbon-nanotube devices

Klaus Kern, Ralf Thomas Weitz, Frederik Sebastian Ante, Hagen Klauk

Nanoscale transistors employing an individual semiconducting carbon nanotube as the channel hold great potential for logic circuits with large integration densities that can be manufactured on glass or plastic substrates. Carbon nanotubes are usually produ ...

2010

Electronic decoupling of an epitaxial graphene monolayer by gold intercalation

Klaus Kern, Ralf Thomas Weitz, Isabella Gierz

The application of graphene in electronic devices requires large-scale epitaxial growth. The presence of the substrate, however, usually reduces the charge-carrier mobility considerably. We show that it is possible to decouple the partially sp(3)-hybridize ...

2010

Highly Reliable Carbon Nanotube Transistors with Patterned Gates and Molecular Gate Dielectric

Klaus Kern, Marko Burghard, Ralf Thomas Weitz, Hagen Klauk

The prospect of realizing nanoscale transistors using individual semiconducting carbon nanotubes offers enormous potential, both as an alternative to silicon technology beyond conventional scaling limits and as a way to implement high-speed devices and cir ...

American Chemical Society (ACS)2009

The Importance of Grain Boundaries for the Time-Dependent Mobility Degradation in Organic Thin-Film Transistors

Klaus Kern, Marko Burghard, Ralf Thomas Weitz, Hagen Klauk

The relationships between organic semiconductor morphology and device stability of organic field-effect transistors (FETs) are very complex and not yet fully understood. Especially For obtaining high-performance, air-stable n-channel FETs, gaining a deep i ...

2009

Bias stress effect in low-voltage organic thin-film transistors

Klaus Kern, Ralf Thomas Weitz, Hagen Klauk

The bias stress effect in pentacene organic thin-film transistors has been investigated. The transistors utilize a thin gate dielectric based on an organic self-assembled monolayer and thus can be operated at low voltages. The bias stress-induced threshold ...

2009

Fabry-Perot Resonances in One-Dimensional Plasmonic Nanostructures

Klaus Kern, Ralf Thomas Weitz

We study the near-field optical behavior of Fabry-Perot resonances in thin metal nanowires, also referred to as quasi one-dimensional plasmonic nanoantennas. From eigenmodes well beyond quadrupolar order we extract both, propagation constant and reflection ...

American Chemical Society (ACS)2009

Electrical properties of functionalized nanowire field effect transistors

Ralf Thomas Weitz

The utilization of functional organic materials holds great promise for applications in electronic devices. Semiconducting organic molecules are frequently used as channel material in field effect transistors, due to the ease by which they can be assembled ...

EPFL2008

Contact and edge effects in graphene devices

Klaus Kern, Kannan Balasubramanian, Marko Burghard, Ralf Thomas Weitz, Eduardo Jian Hua Lee

Electrical transport studies on graphene have been focused mainly on the linear dispersion region around the Fermi level(1,2) and, in particular, on the effects associated with the quasiparticles in graphene behaving as relativistic particles known as Dira ...

2008

Carbon nanotube transistors - chemical functionalization and device characterization

Klaus Kern, Kannan Balasubramanian, Marko Burghard, Ralf Thomas Weitz, Eduardo Jian Hua Lee

This review presents an overview of the recent progress made in the field of carbon nanotube (CNT)-based field-effect transistors (FETs). Starting from the simplest device architectures, various methods reported for fabricating CNT-FETs are presented. The ...

Wiley2008

Polymer nanofibers via nozzle-free centrifugal spinning

Klaus Kern, Stephan Rauschenbach, Marko Burghard, Ralf Thomas Weitz

We report on the unexpected finding of nanoscale fibers with a diameter down to 25 nm that emerge from a polymer solution during a standard spin-coating process. The fiber formation relies upon the Raleigh-Taylor instability of the spin-coated liquid film ...

American Chemical Society (ACS)2008

Plasmonic nanostructures in aperture-less scanning near-field optical microscopy (aSNOM)

Klaus Kern, Alexandre Dmitriev, Ralf Thomas Weitz

Apertureless scanning near-field optical microscopy offers superb spatial resolution, but interpreting the recoreded signal can still be a challenge. Especially images of eigenmodes in plasmonic nanostructures are very often obscured by concurrent scatteri ...

2008

Organic n-channel transistors based on core-cyanated perylene carboxylic diimide derivatives

Klaus Kern, Marko Burghard, Ralf Thomas Weitz, Hagen Klauk

Five core-cyanated perylene carboxylic diimides end-functionalized with fluorine-containing linear and cyclic substituents have been synthesized and employed in the fabrication of air-stable n-channel organic thin-film field-effect transistors with carrier ...

2008

Strong p-Type Doping of Individual Carbon Nanotubes by Prussian Blue Functionalization

Klaus Kern, Marko Burghard, Ralf Thomas Weitz, Eduardo Jian Hua Lee, Adarsh Singh Sagar

2008