Publications de Thomas Kiefer | EPFL Graph Search

Direct imprinting of organic-inorganic hybrid materials into high aspect ratio sub-100 nm structures

Jürgen Brugger, Thomas Kiefer, Victor Javier Cadarso Busto, Vaida Auzelyte

The challenging fabrication of sub-100-nm structures with high aspect ratio by UV-nanoimprint lithography (NIL) is addressed in this work. Thermal shrinkage is induced by cooling the structures below room temperature to avoid the issues commonly arising du ...

Springer Verlag2014

Highly ordered palladium nanodot patterns for full concentration range hydrogen sensing

Jürgen Brugger, Thomas Kiefer, Luis Guillermo Villanueva Torrijo

A hydrogen sensor based on a novel fabrication process that combines the precision of advanced nano-fabrication techniques with a bottom-up process based on electrochemistry is presented. The sensor allows for reliable detection between 0.1% and 100% of H2 ...

2012

Sub micrometer ceramic structures fabricated by molding a polymer-derived ceramic

Jürgen Brugger, Raphael Grandjean, Thomas Kiefer, Jonas Grossenbacher, Rosario Maurizio Gullo

This paper describes the fabrication of sub micrometer silicon oxycarbide (SiCO) ceramic structures. The method consists in replicating silicon micro/nanostructures in polydimethylsiloxane (PDMS), followed by a micro/nano molding of liquid polymer derived ...

Elsevier2012

Biomimetic soft lithography on curved nanostructured surfaces

Jürgen Brugger, Thomas Kiefer, Valentin Flauraud, Victor Javier Cadarso Busto, Vaida Auzelyte

In this paper a nano-molding process using a nature-created master is demonstrated. The eye of night moth Agotis exclamationis having 100 nm-scale structures on a curved surface is used as biomimetic master mold from which nanostructures are replicated ont ...

Elsevier2012

Large arrays of chemo-mechanical nanoswitches for ultralow-power hydrogen sensing

Jürgen Brugger, Thomas Kiefer, Luis Guillermo Villanueva Torrijo, Arnaud Salette

A hydrogen sensor based on large arrays of nanoswitches in palladium (Pd) is presented. An individual nanoswitch is realized by a suspended Pd/Ti/poly-Si trimorph electrode and a fixed Pd/Ti bottom electrode, which are separated by a vertical nanoscopic ga ...

Institute of Physics2010

Very Large Scale Arrays of Chemo-Mechanical Nano-Switches for Ultralow Power Hydrogen Sensing

Jürgen Brugger, Thomas Kiefer, Luis Guillermo Villanueva Torrijo, Arnaud Salette

2010

Pd-functionalized MEMS resonator for hydrogen gas sensing at ambient pressure

Jürgen Brugger, Thomas Kiefer, Luis Guillermo Villanueva Torrijo, Jonas Gustav Henriksson

This work presents the fabrication and characterization of a novel hydrogen-detecting micro-resonator based on the expansion of palladium (Pd) as it is exposed to hydrogen (H2) gas. The working principle of the device has been confirmed and it shows a stro ...

2010

The transition in hydrogen sensing behavior in non-continuous palladium films

Jürgen Brugger, Thomas Kiefer, Luis Guillermo Villanueva Torrijo

The morphological transition in ultrathin palladium (Pd) films around the percolation threshold and the related transition in hydrogen sensing behavior is investigated.We find that besides the transition from continuous to discontinuous Pd, an intermediate ...

American Institute of Physics2010

Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale

Jürgen Brugger, Thomas Kiefer, Luis Guillermo Villanueva Torrijo

Fast hydrogen sensors based on discontinuous palladium (Pd) ﬁlms on supporting polyimide layers, fabricated by a cost-efﬁcient and full-wafer compatible process, are presented. The ﬁlms, deposited by electron-beam evaporation with a nominal thickness of 1. ...

Institute of Physics2010

Hydrogen sensors based on palladium micro- and nanostructures for fuel cell applications

Thomas Kiefer

Hydrogen (H2) has raised considerable interest as a future energy carrier in its application to fuel cell driven vehicles, as it is absolutely free of polluting emissions. However, it is flammable in air and difficult to contain, for which reason innovativ ...

EPFL2009

Direct fabrication of NIL stamps using Stencil Lithography

Jürgen Brugger, Oscar Vazquez Mena, Thomas Kiefer, Luis Guillermo Villanueva Torrijo

Stencil Lithography has been used for the rapid and low cost fabrication of high resolution NIL stamps. The stamps are fabricated by Al deposition through a nanoscale shadow mask and subsequent Si etching. Features down to 50 nm in the stamps have been ach ...

2008

A single nanotrench in a palladium microwire for hydrogen detection

Jürgen Brugger, Oscar Vazquez Mena, Thomas Kiefer, Luis Guillermo Villanueva Torrijo

The hydrogen sensing characteristics of a single nanotrench fabricated by focused ion beam milling (FIB) in an evaporated palladium microwire are presented. In situ atomic force microscopy (AFM) measurements proved that, in the presence of H2, the trench c ...

2008

Design and optimization of nanogap array sensors

Jürgen Brugger, Thomas Kiefer, Luis Guillermo Villanueva Torrijo

We present a percolation based model which is suitable for the design of sensors based on highly ordered nanogap arrays. Monte-Carlo simulations and analytical expressions are used to calculate the sensitivity and dynamic range as a function of the topolog ...

2008

Development of cellular models for ribosomal protein S19 (RPS19)-deficient diamond-blackfan anemia using inducible expression of siRNA against RPS19

Didier Trono, Thomas Kiefer

Diamond-Blackfan anemia (DBA) is a congenital red cell aplasia in which 25% of the patients have a mutation in the ribosomal protein S19 (RPS19) gene. No models exist for RPS19-deficient DBA and the molecular pathogenesis is unknown. To establish an in vit ...

2005

Deficiency of ribosomal protein S19 in CD34+ cells generated by siRNA blocks erythroid development and mimics defects seen in Diamond-Blackfan anemia

Didier Trono, Thomas Kiefer

Diamond-Blackfan anemia (DBA) is a congenital red cell aplasia in which 25% of the patients have a mutation in the ribosomal protein S19 (RPS19) gene. To study effects of RPS19 deficiency in hematopoiesis we transduced CD34(+) umbilical cord blood (CB) and ...

2005