Physical Properties of Multi-wall Nanotubes L´aszl´o Forr´ o 1 and Christian Sch¨ onenberger 2 1 Department of Physics, Ecole Polytechnique F´ ed´ erale de Lausanne 1015 Lausanne, Switzerland forro@igahpse.epfl.ch 2 Department of Physics and Astronomy, University of Basel 4056 Basel, Switzerland christian.schoenenberger@unibas.ch Abstract. After a short presentation on the preparation and structural properties of Multi-Wall carbon NanoTubes (MWNTs), their outstanding electronic, mag- netic, mechanical and field emitting properties are reviewed. The manifestation of mesoscopic transport properties in MWNTs is illustrated through the Aharonov– Bohmeffect,universalconductancefluctuations,theweaklocalizationeffectandits power-law temperature/field dependences. Measurements of the Young’s modulus of individual nanotubes show the high strength of tubes having well-graphitized walls. Electron Spin Resonance (ESR) measurements indicate the low-dimensional character of the electronic states even for relatively large diameter tubes. The con- ductingnatureofthetubes,togetherwiththeirlargecurvaturetipstructure,make them excellent electron and light emitters suitable for applications. With the discovery of Multi-Wall carbon NanoTubes (MWNTs) by Iijima in 1991, a new era has started in the physics and chemistry of carbon nano- structures [1]. After the synthesis of Single Wall carbon NanoTubes (SWNTs) in 1993 by Bethune and coworkers [2] and by Iijima et al. [3], the main stream of carbon research shifted towards the SWNTs, especially through the devel- opment of an efficient synthesis method for their large scale production by Smalley and colleagues [4]. Nevertheless, MWNTs present several comple- mentary attractive features with respect to SWNTs, both for basic science and for applications. For example, one advantage of MWNTs is that they can be grown without magnetic catalytic particles, which are certainly disturbing for magnetic, and probably for transport measurements, as well. The larger diameter of the MWNTs enables us to study quantum interference phenom- ena, such as the Aharonov–Bohm effect, in magnetic fields accessible in the laboratory, while study of the same phenomenon would require 600 T fields in the case of SWNTs. The Russian-doll structure allows better mechanical sta- bility and higher rigidity for the MWNTs which is needed for scanning probe tip applications. Even for making nanotube composites, for which the first step is the chemical functionalization of the tube walls, the multi-wall con- figuration is more advantageous, since efficient load transfer can be achieved without damaging the stiffness of the internal tubes. The paper is organized as follows. First we will briefly review the produc- tion methods for MWNTs. Since the control of sample quality is a condition M. S. Dresselhaus, G. Dresselhaus, Ph. Avouris (Eds.): Carbon Nanotubes, Topics Appl. Phys. 80, 329–391 (2001) c  Springer-Verlag Berlin Heidelberg 2001