Forschung  
Kohlenstoff Nanomaterialien
Molekulares Engineering
Funktionale Oberflächen
Atomistische Simulationen
Infrastruktur

Research Infrastructure
Nanostencil Lithography

We have constructed a novel rapid prototyping platform, which combines nanodevice fabrication with powerful characterization methods. The fabrication method is based on thermal evaporation through shadow masks positioned with nanometer accuracy (nanostenciling). To avoid

contamination and damage of the samples under investigation, the whole set-up is operated under ultra-high vacuum (UHV) conditions. For in-situ characterization we use various high-resolution scanning probe microscopy (SPM) methods and electronic transport measurements. Fabrication and characterization are done at variable temperatures between 30 K and 300 K.

The nanostencil lithography instrument is used for the investigation of technologically important properties, such as charge and spin injection, effects of impurities and interface modifications on organic/inorganic nanostructures. We also explore new concepts for devices based on novel materials, such as organic nanowires, supra-molecular networks, organic/inorganic hybrids, or low-dimensional nanomaterials, which are not accessible using conventional methods. The figure shows an example of a carbon nanotube device fabricated and characterized with the nanostencil lithography instrument

Variable-Temperature STM

This system is based upon an Omicron VT-UHV-STM, permitting STM and STS measurements at the angstrom scale over a broad thermal range (25 K – 1500 K) on metals, semiconductors, and other conducting thin film surfaces. A low current LEED is also equipped for crystallographic investigations.

To make this a more powerful user facility, we designed new sample holders allowing direct sample temperature measurement. We also implemented facilities for in situ sample preparation, including a fine focus ion source, molecule evaporation sources with crucibles in situ exchangeable, quartz crystal microbalance and a liquid/gas doser. The manipulator can be cooled down to ~110 K. This system covers virtually all possible applications involving dynamic processes on surfaces, such as molecule adsorption and diffusion, chemical reactions, film nucleation and growth, phase transitions, etc.

Low-Temperature STM

Our Omicron LT-STM is a dedicated instrument for scanning tunneling microscopy and spectroscopy investigations at very low temperatures. The set-up is mostly operated at a temperature of 5K (liquid helium cooling) or 77K (liquid nitrogen cooling) with an outstanding thermal stability (drift 0.3nm/day @ 5K).

The instrument achieves a z-stability in the range of 1 pm allowing high resolution topographic imaging. Attached to the STM analysis chamber we have an autonomous vacuum chamber in which the sample preparation can be performed. The sample temperature on the manipulator in this preparation chamber can be varied between 100 K and 1150 K to perform molecular adsorption at low temperatures or single crystal annealing followed by sputter cleaning of the surface. On different ports of the preparation chamber we have the following tools attached: Omicron Specta LEED; Electron cyclotron resonance (ECR) plasma source; E-beam heating station. We have further the possibility to evaporate molecules directly into the STM during sample scanning.

ESCA

UHV system consisting of an analysis chamber (base pressure <5 x 10-11 mbar), two preparation chambers (base pressure 1 x 10-10 mbar) and a fast entry lock.

The analysis chamber is equipped with a 5-channeltron electron energy analyser (0-2000V kinetic energy), a computerized full-hemisphere goniometer, Al- and Mg-kalpha X-ray source, monochromated Al-k-alpha x-ray source, He I/II-UV lamp for X-ray photoelectron spectroscopy / diffraction (XPS / XPD) and Angle resolved ultraviolet photoelectron spectroscopy (ARUPS) respectively. The preparation chamber is equipped with standard surface preparation capabilities, several metal and molecule evaporators, a LEED and a combined room temperature UHV-AFM / STM.

PES-/Qplus System

Our newest system is based on two main analytical UHV chambers, one hosting the PES system and the other hosting the LT-SPM. Both chambers are placed on individual benches and are vacuum connected by a vibration free transfer line.

Dedicated preparation chambers are attached to both analysis chambers. This instrument combines an Omicron low-temperature Q-Plus STM/AFM with an ARPES System from Scienta, including these features:

 

-He-cooled ARPES manipulator (24 K)

-LEED-I(V) -6 fold evaporators

-Coolable preparation manipulator

Plasma Chamber

Our plasma facilities are mainly used to fabricate functional thin films for technological relevant processes.

The HV Plasma Chamber is a homemade system consisting of a HV chamber coupled to a microwave (2.45 GHz) reactor working in Electron Cyclotron Resonance (ECR) conditions. This configuration enables the deposition at low pressures down to 10-5 mbar. This system is used to fabricate functional thin films by a plasma assisted deposition like PECVD for inorganic oxides or Plasma polymerization of organic molecules, among others.

BlackMagic

BlackMagic 2 inches: This is a commercial system to deposit carbon based structures like Carbon Nanotubes (CNTs) and graphene by CVD. Different hydrocarbon gases can be used for CVD growth such as ethylene, acetylene, methane, alcohols, etc. In addition, a DC plasma (either in continuous or pulsed regime) can be applied to the samples to fabricate Vertically Aligned CNTs that own extraordinary cold electron emission properties.

Scanning Anode Field Emission Microscope

We have constructed a novel UHV scanning anode field emission microscope (SAFEM) where the field emission current is extracted by a small spherical anode brought, at micrometric proximity, in front of a planar cathode surface.

SAFEM is used to map the electron emission current I(x,y) under constant anode voltage and the electron extraction voltage V(x,y) under constant emission current as a function of tip position on all kind of emitters.

GNR Reactor

The GNRreactor is a simple, low-cost stand-alone vacuum system designed for the implementation of an industry compliant GNR fabrication process and scaling up of sample production for device development. It consists of a vacuum chamber

with a turbomolecular pump, a fast entry lock for quick exchange of samples, a retractable sample stage with integrated heater and thermocouple, a six-fold evaporator for deposition of precursor monomers, and retractable thickness monitor. The deposition process is entirely automated with pre-defined recipes in the easy-to-use software interface, meaning that processes developed on user- and time-intensive STM systems can be readily transferred to the GNRreactor to increase production. In fact, sample preparation time is dramatically reduced: 12 samples per day in the GNRreactor, compared to 3 samples per day in an STM system. Relatively low-cost Au/mica substrates – compared to single crystal substrates – are used for sample preparation, which can then be used for more detailed ambient characterization and device development.

Electro- & Chemistry / Nanoscope III

This Lab is equiped for all kind of experiments in liquids and electrolytes, but also for the preparation of STM-tips and determination of molecule deposition rates. Therefore, it contains several equipments:

Nanoscope III Multimode from Veeco:

Multi purpose scanning probe microscope for STM and AFM in air and in electrolytes under electrochemical control with the possibility to apply an inert gas atmosphere. Scan range from atomic resolution to 130 um. Various homebuilt electrochemical cells with microelectrodes also for non-aqueous electrolytes. Optical access by a high resolution optical microscope to locate the probe on the sample. Signal Access Module from digital instruments to read out and feed in all relevant signals.

Tip etching facility:

Setup for electrochemical etching of PtIr-tips in a salt melt and W-tips in aqueous electrolyte. Setup for insulating tips with Apiezon wax for electrochemical measurements.

µAutolabIII:

Potentiostat/Galvanostat for electrochemical characterisation. Water with a resistivity >18.2 MOhm cm is obtained by the Purelab Ultra Ionic system from ELGA.

SRD-Setup:

Equipped with calibrated evaporation source and quartz crystal microbalance to determine fully automized the deposition rate of molecules prior to UHV experiments

Ipazia computer cluster

Ipazia is part of the swiss high performance computing strategy. Medium-sized applications that can not be run on desktop computers, and still are not suitable for an efficient exploiting of the supercomputers in the Swiss Center for Scientific Computing in Lugano, are expected to find powerful and reliable hardware and software resources in commodity clusters built withing the single research institutions.

Ipazia hosts "parameter space spanning" jobs like environmental models or flight traffic noise monitoring, tipically represented by a wealth of single-processor calculation runs, through small multiphysics parallel jobs for the analysis of materials, to efficient multiprocessor parallel jobs for complex and predictive atmospheric models and high-level ab initio calculations applied to nanoscience. Examples of the latter research projects are the studies conducted in our laboratory on the themes presented in these web pages. All the aforementioned applications find in Ipazia (now reaching 7 Teraflops of peak performance) advanced interconnection protocols, large memory and cpu performance, and a fast and reliable storage system (presently 40 Terabyte).

ADDRESS

nanotech@surfaces Laboratory

Empa, Swiss Federal Laboratories for

Materials Science & Technology

Ueberlandstrasse 129

8600 Duebendorf

Switzerland

How to find us :

printable map, interactive map

 

CONTACT

Prof. Dr. Roman Fasel, Head of Laboratory

Dr. Oliver Gröning, Deputy head

Ms. Christine Tran, Head assistant

zurück  Links  Druckansicht