Physics of objects with micron or nanometer dimensions under miscellaneous forms is a general theme, rich in past successes and future projects in the Triangle de la Physique. For several decades, with the progress in elaborating complex materials and structures controlled to within one atomic layer, the opening of new fields has been made possible, both in semi-conductor physics and magnetism and more recently with functional oxides.

This work resulted in many modern components, such as two-dimensional gas transistors, lasers and quantum well detectors, quantum cascade lasers, and during this last decade, magnetic components for spin control. In this respect, the internationally recognised essential and durable role of certain laboratories within the network should be noted: TRT, UMR CNRS/Thales, LPN, and IEF.

 

The research field was again widened by introducing technologies from microelectronics, which today allow structuration of complex objects such as quantum wires, wells, pillars and boxes. Very often, original effects have thereby discovered and studied; these advances are clearly based on the development of manufacturing technologies and on the involvement of physicists in that development. Access to the highest performing manufacturing and synthesis tools and techniques is therefore necessary in order to have available new objects of study with original properties potentially promising for industrial developments. The importance and complementarity of the means to be applied for conducting this kind of studies assume an unquestionable concentration of means and of skills.

In this sense, the existence of technological platforms superiorly equipped at several sites of the Triangle de la Physique, i.e. in the LPN of Marcoussis, MINERVE in the IEF at Orsay, on the X-IOTA-Thales campus, is an obvious strength. The first two belong to the national network of large technology centres for Basic Technological Research (BTR), intended to provide the technologies required for conducting research projects of laboratories in the field of micro/nano-technologies and nanosciences. The LPN is specialized in technologies of semiconducting nanostructures, mainly heterostuctures of III-V semiconductors, and in their structuration. MINERVE exhibits specific curricula in nanomagnetism and spin electronics, nano-optics and microsystems. Finally, the X-IOGS-Thales platform groups together a set of consequent means for microelectronics technology, along with analytical tools. It covers the field of (III/V, Si) semiconductors, metals and organic materials, and LIGA technology is available. Moreover, it has a training room for students. Insofar as emphasis today is often placed on the study of physical properties of individual objects, all the possibilities provided by the new lithographic and ion machining tools for making the required contacts, junctions and connections, and their integration in vaster architectures, are a valuable asset for all measurements of transport and magnetism on mesoscopic or nanometric objects (carbon nanotubes, for example). An obvious strength for proposing ambitious and original research projects is the combination of these manufacturing tools with the means required for fine characterization, which may go beyond the ultimate limits accessible with the future SuperSTEM of the LPS Orsay (another component of the MINERVE project of the UPS).

This top-down approach in fact is only one of the possibilities provided for creating nanostructures. Another approach of the bottom-up type, particularly attractive when working on sets of self-organized objects is desired, consists of nucleating and growing the objects from constitutive atoms or molecules. Particularly fast development of these techniques may be seen in emerging scientific countries (China, Korea, but also Japan). In this field, skills are numerous and complementary in the Triangle de la Physique. In the physical bottom-up approach, preformed aggregates of a few ten or hundred atoms are generated and deposited on a surface in a controlled way. The LAC at Orsay has been established for several years as an international leading centre of this technique, which provides original possibilities for controlling size, density and shape of the nano-objects. Other so-called thermodynamic paths have been explored on the campus: they are applied in epitaxy, MBE or other techniques, and with them, it has been possible to make networks of quantum boxes (LPN, IEF) and metal aggregates (UMR CNRS/Thales). A very effective approach resorts to basic chemistry methods, which are particularly well mastered at the CEA Saclay. With the matrix growth method practiced at the LSI (Ecole Polytechnique/CEA), it has been possible to simply make a large variety of different systems - magnetic nanowires, semi-conductors, carbon nanotubes, etc., and to thereby study transport mechanisms within a single 1D object, and illustrate the universality of the laws governing it. With nanochemistry, which makes use of organized fluids, charged copolymers, and cage molecules, nanomaterials may be obtained with original properties. In every case, better understanding of growth mechanisms in the liquid or gas phase and of diffusion on surfaces and supporting membranes, widely contributes to having these diversified skills evolve towards real engineering of the nucleation and growth of structures with targeted properties.