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Jeudi 3 Avril 2014, 14h
Amphi Holweck, Esc C, 1ème etage
Two-dimensional colloidal nanostructures : Synthesis and electrical transport
Christian Klinke
University of Hamburg
Coulomb blockade and oscillations had been observed in individual nanoparticles (e.g. Andres et al., Science 272 (1996) 1323 ; Klein et al., Appl. Phys. Lett. 68 (1996) 2574). In my talk I will demonstrate that by means of a local top-gate current oscillations can be observed also in extended, monolayered films assembled from monodisperse metal nanocrystals realizing transistor function. The oscillations in this metal-based system are due to the occurrence of a Coulomb energy gap in the nanocrystals which is tunable via the nanocrystal size. Further, I will show that the formation of ordered and densely packed ligand surface layers of oleic acid on 100 PbS surfaces can drive the normally isotropic crystal growth into a two-dimensional oriented attachment of nanocrystals. Hereby the presence of chlorine containing co-solvents during the initial nucleation and growth process of the nanocrystals plays a prominent role. The synthesis and the formation mechanism will be discussed, as well as first electrical applications.