Charge Carrier Transport in 1-dimensional Arrays of Nanoparticles
L. Govor, J. Parisi, G.H. Bauer (CvO University Oldenburg and R. Haug Leibniz-University Hannover)
Funded by DFG 2007-2009
The research program focuses on the analysis of charge transport in quantum states of metallic nanoparticles arranged in 1-dimensional arrays (lines/chains). The diameter of the nanoparticles amounts to 6 nm with fairly narrow size distribution and the average distance in between is in the neighborhood of 3 nm. The disorder governing charge transport properties mainly results from fluctuations in the particle position and comparatively negligibly from particle size variations. Respective studies of hopping currents in dependence of relevant control parameters such as electric and magnetic field strengths, and temperature (4.2 K – 300 K) and as function of number of aligned chains, as well, we expect direct experimental access to relations for the formulation of single elementary (electron) charge transport including the effects of Coulomb-blockade, energy level quantization, single-electron-tunneling, low dimensional variable range hopping, and phenomenologically based Arrhenius-relations. In a further approach the application of ferromagnetic nanoparticles allows for analyses of spin-dependent transport in 1-dimensional quantum states arranged with primarily positional disorder.
Figures 1a, 1b, 1c, 1d: TEM pictures of circular arrangements of CoPt3 in one, two, three and four lines/chains by wetting/dewetting phase decays of spreading solvent layers doped with CoPt3 in different concentrations (insets show magnification of CoPt3 structures at positions indicated by arrows).