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Klaus Kern

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Publications associées (299)

Kondo-effect of substitutional cobalt impurities at copper surfaces

Klaus Kern, Peter Wahl

The influence of the coordination on the Kondo temperature of a magnetic impurity at a noble metal surface and the line shape observed in low temperature scanning tunneling spectroscopy (STS) is investigated for single cobalt atoms adsorbed on and embedded ...

2009

Electrical Conduction Mechanism in Chemically Derived Graphene Monolayers

Klaus Kern, Marko Burghard, Ravi Shankar Sundaram

We have performed a detailed study of the intrinsic electrical conduction process in individual monolayers of chemically reduced graphene oxide down to a temperature of 2 K. The observed conductance can be consistently interpreted in the framework of two-d ...

American Chemical Society (ACS)2009

Substrate effect on supramolecular self-assembly: from semiconductors to metals

Klaus Kern, Dietmar Payer, Theresa Lutz, Giovanni Costantini

Terephthalic acid (TPA) deposited on Si(111)-7 x 7, Si(111)-root 3 x root 3-Ag and Ag(111) has been studied as a model system to understand how much passivated semiconductor surfaces differ from semiconductor and metal surfaces in respect of supramolecular ...

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

Potential energy landscape of metallic Moire patterns

Klaus Kern, Peter Wahl

The modulation of the electronic structure of cobalt islands on Cu(111) by the Moire pattern of an Ag overlayer is investigated. Acquisition of tunneling spectroscopy maps reveals a local modification of both the energy and the amplitude of the cobalt-rela ...

2009

Two-dimensional metal-organic coordination networks of Mn-7,7,8,8-tetracyanoquinodimethane assembled on Cu(100): Structural, electronic, and magnetic properties

Klaus Kern, Tzu-Chun Tseng

A compound two-dimensional (2D) monolayer mixing Mn atoms and 7,7,8,8-tetracyanoquinodimethane (TCNQ) molecules was synthesized by supramolecular assembly on a Cu(100) surface under ultrahigh vacuum conditions. Its structural, electronic, and magnetic prop ...

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

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

Full simulations of the apertureless scanning near field optical microscopy signal: achievable resolution and contrast

Klaus Kern

We simulate apertureless near-field optical imaging and obtain phase and amplitude scans of structured substrates for elastic scattering. The solution of the three-dimensional Maxwell equations does not involve approximations and we include large tips and ...

2009

Vertical arrays of nanofluidic channels fabricated without nanolithography

Klaus Kern, Kannan Balasubramanian, Floriano Traversi

Vertical arrays of sealed nanofluidic channels, in which both cross-sectional dimensions are controllable down to 10 nm, were fabricated by selective side etching of a SiGe heterostructure comprised of layers of alternating Ge fractions. Capillary filling ...

2009

Supramolecular control of the magnetic anisotropy in two-dimensional high-spin Fe arrays at a metal interface

Harald Brune, Klaus Kern, Pietro Gambardella, Sylvain Clair, Alexandre Dmitriev, Sebastian Stepanow, Magalí Alejandra Lingenfelder

Magnetic atoms at surfaces are a rich model system for solid-state magnetic bits exhibiting either classical(1,2) or quantum(3,4) behaviour. Individual atoms, however, are difficult to arrange in regular patterns(1-5). Moreover, their magnetic properties a ...

Nature Publishing Group2009

Applications of the Static Quenching of Rhodamine B by Carbon Nanotubes

Klaus Kern, Kannan Balasubramanian

We report here on the interaction of the fluorescent dye rhodamine B (RB) with single-walled carbon nanotubes (SWCNTs). We observe that SWCNTs statically quench the fluorescence of RB by forming a stable ground state complex. Careful spectroscopic analysis ...

2009

Carbon-Based Field-Effect Transistors for Nanoelectronics

Klaus Kern, Marko Burghard, Hagen Klauk

In this review, the suitability of the major types of carbon nanostructures as conducting channels of field-effect transistors (FETs) is compared on the basis of the dimensionality and size of their pi-conjugated system. For each of these materials, recent ...

Wiley2009

Spin-orbit split two-dimensional electron gas with tunable Rashba and Fermi energy

Klaus Kern, Marco Grioni, Daniela Pacilè, Luca Moreschini

We demonstrate that it is possible to tune the Rashba energy, introduced by a strong spin-orbit splitting, and the Fermi energy in a two-dimensional electron gas by a controlled change of stoichiometry in an artificial surface alloy. In the BixPb1-x/Ag(111 ...

2008

Does the Surface Matter? Hydrogen-Bonded Chain Formation of an Oxalic Amide Derivative in a Two- and Three-Dimensional Environment

Harald Brune, Klaus Kern, Sylvain Clair, Marta Canas Ventura, Uta Schlickum

We report on a multi-technique investigation of the supramolecular organisation of N,N-diphenyl oxalic amide under differently dimensioned environments, namely three-dimensional (3D) in the bulk crystal, and in two dimensions on the Ag(111) surface as well ...

2008

Metal-organic coordination interactions in Fe-Terephthalic acid networks on Cu(100)

Klaus Kern, Giovanni Costantini

Metal-organic coordination interactions are prime candidates for the formation of self-assembled, nanometer-scale periodic networks with room-temperature structural stability. We present X-ray photoelectron spectroscopy measurements of such networks at the ...

2008

Surface enhanced Raman scattering of carbon nanotubes decorated by individual fluorescent gold particles

Klaus Kern, Kannan Balasubramanian, Tilman Assmus, Marko Burghard

Confocal optical microscopy was employed to study the effect of surface-enhanced Raman scattering on individual single-walled carbon nanotubes covered with isolated gold particles. The gold particles with diameters between 10 and 120 nm were deposited in l ...

2008

Effect of the electronic structure of carbon nanotubes on the selectivity of electrochemical functionalization

Klaus Kern, Kannan Balasubramanian, Marko Burghard

The functionalization of carbon nanotubes through electrochemical routes is gaining importance due to the high degree of control achievable and the ability to render the tubes with a variety of chemical and biological species. In this article, we report sy ...

2008

Atomic Hole Doping of Graphene

Klaus Kern, Isabella Gierz

The application of graphene in nanoscale electronic devices requires the deliberate control of the density and character of its charge carriers. We show by angle-resolved photoemission spectroscopy that substantial hole doping in the conical band structure ...

American Chemical Society (ACS)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

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