RICERCA ITALIANA     

Centro di Eccellenza per la Preparazione -Sviluppo e Caratterizzazione- di Materiali e Superfici Nanostrutturate

Università degli Studi di Trieste

Principal Investigator

Renzo ROSEI Università degli Studi di TRIESTE

Research Objectives

4.1 IntroductionIn the last decade, the development of electron microscopes with extremely high resolution, the availability of X-Ray microscopes at the third generation synchrotron radiation facilities and above all the exceptional possibilities offered by the Scanning Tunneling Microscopes, have radically changed the way we conceive and interact with matter at the level of single atoms and molecules. The structure and operating principles of the new experimental methods have encouraged the exploration of the nanometric world much above the simple conventional microscopic imaging. Modern techniques, based on "scanning probe" instruments, make it possible to perform surface engineering at the level of single atoms, molecules and chemical bonds, yielding therefore instruments that operate at the extreme spacial limits of the fabrication processes. It has thus become possible to investigate the chemical/physical, electronic and mechanic properties of single adsorbed molecules, without using the standard statistichal methods.The progress in this field has been so fast to suggest the possibility of a completely new way to tackle the nanofabrication problems: the bottom-up approach could be eventually competing with the conventional top-down one for the development of future nanotechnologies. The top-down method refers to the attempt of continuing the miniaturization process via a simple extension of the already available microfabrication processes. The bottom-up approach, instead, tries to directly build nanostructructured surfaces, with an increasing level of complexity but always controlling the process "atom by atom".The attempt to reach submicron dimensions has motivations that differ according to the desired technological application: from smaller and smaller chips to increase the processor speed, to the nanometric ceramic powders that allow moulding methods up to now possible only with metals, to the micromechanic devices for clinical/medical applications, to the carbon nanotubes for focalised electron emissions.Indipendently of the particular application, it is clear that the investigation of such materials requires methods capable of providing meaningful experimental data on the same spacial scale of the nanostructured materials. In this respect, we can say that nowadays some of the fundamental characterization methods available to the researchers yield useful informations at a spacial dimension below which they cannot yield meaningful information about the functional and structural characteristics of the nanostructured materials.On the other side, in the scientific field of the computational "ab initio" methods, which was until recently separated from the material science and technology field, the above mentioned problem was completely opposite. The power of the available computers allows to obtain very detailed information about the electronic structure and the geometric arrangement of the nuclei on a spacial scale up to a few nanometers at most.In this respect the computational methods work at a spacial scale above which it is practically impossible to obtain information of scientific or technologic relevance, within reasonable time and costs.Paradoxically, there is general agreement that with the presently available instruments, science and technology of nanostructured materials are more advanced in the preparation than in the characterization methods, and that the dimensional scale in which data mostly needed is the nanometric one. An example of this can be found in the July 2001 issue of the Materials Research Society Bulletin, which publishes a review of the field of "nano-materials". Several images of nanometric devices are presented, but there is not a single graph that shows data or variations of their characteristics on the same dimensional scale.The Physics, Chemistry and Materials Engineering Departments of the University of Trieste host some research groups that have been operating in this field for many years, obtaining very interesting results. Such groups, besides interacting among themselves, have estabilished strict collaborations with some of the most advances scientific enterprises at the Area Science Park in Trieste, such as the TASC-INFM laboratory and the Sincrotrone Trieste S.C.p.A..Altogether, these groups have a well estabilished experience about both the scientific and the techological and engineering issues regarding nanostructured materials and surfaces. Even more important is the extremely advanced instrumentation related to this field which is available to them, both at the University facilities and at the above mentioned extra-University facility, on the basis of specific official agreements. Particularly important in the present framework are the instruments for advanced nanoscopy (two AFM, two STM, one electron microscope, one High Resolution TEM, one experimental station for synchrotron radiation nanoscopy in the soft X-rays and one in the extreme ultraviolet regions). The availability of this highly sophisticated instrumentation and the experience in its use make this group of researchers unique in Italy and with few comparisons in Europe.4.2 OBJECTIVES OF THE EXCELLENCE CENTERThe first objective of the Center is the one of intensifying the collaborations among the proponent groups with the aim of maximising the possible synergies. Considering the existing competences, which cover different fields (surface physics, materials engineering, basic catalysis and its industrial applications, nanostructured surfaces, optoelectronic devices, computational physics, etc.) which well complement each other, it is easy to foresee the possibility of realising an Excellence Center with unique characteristics in Italy, both for grouped expertises and for existing instrumentation.The second objective is to acquire new instrumentation or properly complete the existing one, in order to make it possible to carry out research activities competing at the world top level. Novel instrumentation, such as the "Pulsed MOCVD", the L-He STM for nanomanipulation for the production of nanostructured materials and surfaces will be built or acquired; advanced instrumentation for the nanocharacterization will be completed or set up, such as the UHV expansion of the existing High Resolution TEM, the SNOM-Raman, the AFM for liquids and a reactor coupled to a gas handling system and mass-spectrometer for the analysis of the chemical reactivity of the obtained materials.Besides the acquisition of new instrumentation, the first three years of the Center will be mainly dedicated, to experiments of new kind, as detailed in the Research Plan (Section 6). In particular, interdisciplinar research will be stimulated, in order to maximise the cultural and experimental synergies, and the integration between theory and experiment. We plan also to take advantage of the cultural environment created by the new activities for an educative and formative action which will lead to new professional profiles. These will help both in fulfilling the needs of personnel of the Center in short times, and in a progressive substitution of the staff in longer times.4.3 OBJECTIVES OF THE EXCELLENCE CENTER IN LONGER TERMS.In the long run the success of the Center will be measured mainly by its capability of attracting industrial contracts, transferring know-how to the industry and fostering technical innovation. To this purpose, the integration of the new professional personnel formed at the Center with the most active industries of the country will provide a further boost to the production activities. <<<