The research group Nanotech@Surfaces has been established on the 1.1.2003 as division 127 at the Swiss Federal Laborato-ries for Material Testing and Research (EMPA) in Thun. It has been formed out of members of the solid state physics research group of Prof. Louis Schlapbach of the University of Fribourg and is headed by Dr. Pierangelo Gröning.
The research of the group focuses on self-assembly and characterization of organic molecules at surfaces, plasma-enhanced chemical vapor deposition of plasma polymers and carbon nanostructures as well as on fundamental aspects of the electronic properties of carbon nanotubes and their application as field electron emitter.
Reseach activities
he investigation of the electronic properties and the electron field emission behavior of carbon nanostructures are at the center of our research group. Of particular interests are the influence of point defects on the local electronic structure of sp2 coordinated carbon and the electron field emission properties of carbon nanotubes (CNT), CNT thin films, and well ordered CNT arrays.
In recent years carbon has attracted much interest as a possible post-silicon electronic material, due to the variety of stable allotropes with completely different electronic properties. In particular, the discovery of the CNT in 1991 has motivated a large number of studies of their electronic and mechanical properties in view of potential applications for electronic devices on the nanometer scale.
The field emission of electrons is regarded as one of the first application of CNT with a major economic impact. The main reason for the success of CNT field emitters can be seen in the relative ease and the low cost approaches to produce planar electron emission cathodes. The performance of a planar field emission cathode will be mainly determined by following four parameters: Cathode emission current density [Acm-2], Emission site density (ESD) [cm-2], applied field for operation [Vμm-1] and temporal stability or life time of the cathode. These parameters are connected by a complex relation between the geometrical structure of the field emission cathode as well as the CNT materials and electrical contact properties to the substrate. Using the homebuilt scanning anode field emission microscope (SAFEM) we are able to investigate all the relevant emission properties down to the micrometer scale in order to gain more insight in the mechanisms determining the performance of the field emission cathode. Currently we are involved in different projects with industrial partners as Thales S.A. (France), SONY Corp. (Japan), and Mapper Lithography (Netherlands) to develop devices based on CNT field emitters.
References
P. Ruffieux et al., Phys. Rev. Lett. 84, 4910 (2000).
P. Ruffieux et al., Phys. Rev. B 66, 245416 (2002).
O. Gröning et al., CHIMIA 56, 553 (2002).
P. Gröning et al., Adv. Eng. Mat. 5, 541 (2003).
Read the scientific article published in MaNEP Newsletter No. 4 (PDF. 328 Ko)
Read a basic introduction to Electron Emmission using Carbon Nanotubes
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