Report on the Franco-Israeli Workshop on
"Characterization of Materials at Nano-Meter Scale"
and the visit of the French delegation
Jerusalem, 25-29 September, 2000
By A. Bourret and Y. Lereah
The Franco-Israeli Workshop on Characterization of Materials at Nano-Meter Scale was held
at the Olive Tree Hotel on September 25-26, 2000 and was followed by a visit at the Tel Aviv
University on September 28. The workshop and the visit were co-sponsored by the Ministry
of Science, Culture and Sport of Israel, and the Ministry of Foreign Affairs of France. It was
also supported by the Tel Aviv University. The French delegation has also been offered by the
Ministry of Science, Culture and Sport a guided tour in Jerusalem.
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Scope of the workshop
The recent development of nanosciences, and the important technological applications to be
expected, have induced a variety of research in order to understand the new phenomena
associated with systems of very small dimensions. One of the key points is the progress
achieved in a better control and characterization of nano-objects: it is essential to know
precisely the structure and composition at nanometer scale. In this field both Israel and France
are engaged. "Nanotechnology" is a first priority of the Ministry of Science in Israel, and
similarly several research programs have been launched in France by the Ministry of Research
or by the scientific agencies (CNRS and CEA). It is understood in both countries that the
future development of the microelectronics as well as optoelectronics (or all the technology
using them) are dependent on the efforts put on research in nanosciences.
The research on nanosciences has always three interconnected aspects:
making the small objects
measuring their properties
analyzing the atomic structure and the local composition of these objects
The scientific scope of the workshop has been concentrated on the latter aspect: several
methods are available and potentially efficient at nano-scale. During the workshop each
method has been presented by specialists. A comparison between the methods was discussed
at the round table discussion.
Organizers
The organizing Committee was the following :
Bourret Alain- CEA Grenoble, co chairman
Lereah Yossi - Tel Aviv University, co chairman
Cohen Sidney- Weitzmann Institute
Deutsch Moshe- Bar Ilan University
Kaplan Wayne- Technion
Rosenfeld Elieser- Ministry of Science, Culture and Sport
Shimony Beky- Ministry of Science, Culture and Sport
Audience
54 participants were attending the two-day workshop (see list, appendix A). Among the Israeli
attendance, 10 Israeli institutions (including industry) were represented. Hence the workshop
has successfully covered the main scientific research teams working on nanosciences in Israel.
The French delegation, on the other hand, was composed of 10 scientists and was
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geographically representative of the main French cities involved in the characterization of
nanostructures (with the exception of Toulouse and Marseille ).
In addition, participants from 2 Palestinian Universities were attending.
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Scientific contributions
The scientific program (Appendix B) included 14 invited talks (7 Israeli and 7 French), 10
posters (9 Israeli and 1 French) and a round table discussion with five scientists in the panel.
Three characterization methods were presented by the invited speakers :
X-rays
Electron microscopy
Scanning probe microscopy
These selected methods are very representative of those mainly used today and in the near
future for characterization of nanostructures (in academic research as well in applied research
or in the industry). For each method, the results of the discussions during the workshop will
be summarized below:
X-rays :
The advent of high brillance X-rays synchrotron sources has opened up a variety of new
applications in the field of surface, near surface and small particles studies. This has been
clearly illustrated on liquid surfaces and overlayers in metals and metal alloys by M. Deutsch.
The fluctuations of lipidic membranes as well as their deformation properties can be extracted
from grazing incidence x-ray scattering as shown by J. Daillant. A. Naudon has developed the
grazing-incidence small-angle X-ray scattering in order to measure the morphology of
deposited nanoparticles: the correlation between particles may as well be deduced. Similarly
Y. Cohen has illustrated the advantage of small angle scattering in the range 10-100 nm.
The most important advantage of the X-ray methods is that they give quantitative
measurement, they are non-destructive and the result is an average over a large assembly of
particles or a large surface. However the interpretation of the scattering is often model
dependent and all the participants agreed for the necessity to obtain complementary results by
an imaging method. This was illustrated by Y. Cohen in the study of block copolymers for
which valuable information has been obtained from electron microscopy.
The recent official participation of Israel in the European Synchrotron Radiation Facility at
Grenoble is an excellent opportunity for a French-Israeli collaboration in the field of
nanostructures. M. Deutsch, the actual representative at the ESRF Council will maintain the
contact with the French groups.
Electron microscopy :
Although essentially an imaging method, the electron microscopy is also able to perform
electron diffraction. JP Morniroli has shown the advantage of convergent beam electron
diffraction especially at large angle (LACBED) to study small particles and crystal structure
at small scale. The high resolution electron microscopy gives information at 0.1nm scale and
a large variety of studies were performed at in metal-ceramic interface (W. Kaplan), catalyst
particles and metallic compounds (T. Epicier), grain boundaries segregation (JM Penisson) or
nanotubes (A Loiseau). All the speakers insisted on the advantage of complementing imaging
by electron energy loss spectrocopy ( EELS) or X-ray spectroscopy. The recent development
of EELS and of energy filtered image enables now to obtain chemical and electronic
information at nanometer scale. The speakers also insisted on the advantage of a multi method
instrument in which imaging, diffraction and nano-analysis are possible. Field emission guns
authorize such a versatility.
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In the field of soft matter and comlex fluids, the cryomicroscopy method has also proven to be
efficient (Y. Talmon): such a method may well be interesting for solids of low melting point
(very small particles) or for radiation sensitive materials.
Electron microscopy has a large impact on science and technology due to its rather direct type
of information given by an image. The local and precise information is also of great
advantage, although the result may be statistically not always significant. The disadvantage is
a rather long and destructive specimen preparation, and the projection problem (an image is
always a projection of a 3D object)
Scanning probe microscopy
Since the invention of the scanning tunneling microscopy (STM) a large variety of
instruments have been developed and applied to a number of materials. This has been
illustrated by S. R. Cohen for studying the surface electronic characterization by Kelvin probe
microscopy or scanning capacitance microscopy. STM has the atomic resolution and has been
widely used to study nanoparticles on heteroepitaxial surfaces (I. Goldfarb), defects, diffusion
and coallescence at surfaces (Y. Manassen). But STM is also a tool to study chemical reaction
at surfaces or to trigger molecular reaction by atomic manipulations (G. Dujardin). The results
so far obtained on the early stage of the epitaxial growth are impressive and the development
of this method for small deposited particles could be easily foreseen. Like for electron
microscopy the image interpretation is not straightforward and the simulation codes are still in
their infancy. However the mehod is generally easy to use, versatile (many different signals
could be measured simultaneously) and relatively inexpensive in its ordinary form. The main
disadvantage is its limitation to study surfaces or small objects (nanometer scale) deposited on
surfaces. For embedded objects the only available technique is the electron microscopy.
Tel-Aviv University visit
The one-day visit to the Tel-Aviv University has given to the French delegation an overview
on the activity at the Faculty of Engineering. Of particular interest were the new project of a
Center for nanoscience and technology and the well equipped Central Facility for
Characterization.
Conclusions
Scientific and technical conclusions:
The original subject of the workshop, with specialist of different characterization techniques
working at the same nano-meter scale irrespective of the materials, has been proven to be very
successful. Most of the participants, familiar with only one technique, were not aware of the
potentiality of the other techniques. For instance one of the most important conclusion is that
imaging and diffraction method should be always both employed on the nano-objects:
although very often said, this conclusion is rarely practically applied.
In addition it has been realized that an easy access to instruments of high quality is of prime
importance for laboratory or industry working on nanotechniques. As a consequence large
analytical facility at a scale of a university or a nation is often necessary and should be well
supported. This is not the case for AFM and perhaps STM, low cost instruments which can be
implemented in any laboratory.
For synchrotron facilities, the time delay should be reduced in one way or the other.
Dedicated beam lines for nanostructure characterization by GISAXS or surface diffraction
could be envisaged with special fast procedure for project selections. Moreover the
construction of a national electron microscope center close to a synchrotron facility seems
very attractive and should be encouraged.
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Franco-Israeli collaborations :
A fruitful collaboration between Tel Aviv University, Nice and Grenoble has been developed
for a long time. The new acquisition of a field emission electron microscope at TAU will
enhance this collaboration on the study of small particles.
Concerning X-rays, the contacts at ESRF Grenoble should be developed. The groups of A.
Naudon at Poitiers and G. Renaud at Grenoble are specially interested in developing such a
collaboration.
In the case of scanning probe microscopy, G. Dujardin has contacted different groups at BenGurion University and at Technion with which future common projects will be presented.
In addition, full account of the diverse supports available for common Israeli-French projects
has been given by the Ministry or Embassy representatives, in particular the Israeli Chief
Scientist, and the Attaché Scientifique from the French Embassy.
Finally the participants as well as the organizers were all convinced that a new meeting on the
same subject in two years from now, should be organized in France.
Appendix A
List of participants
Appendix B
Scientific Program
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