02499nas a2200205   4500008004100000022001400041245012900055210006900184260007300253300001400326490000800340520166300348653001902011653004002030100001902070700002802089700001902117700002602136856013102162       2007                        eng d  a0169-433200aScanning tunneling microscopy/spectroscopy on Au nanoparticles assembled using lauryl amine (LAM) and octadecane thiol (ODT)0 aScanning tunneling microscopyspectroscopy on Au nanoparticles as  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAR  a5109-51150 v2533 a<p>In this report, we demonstrate scanning tunneling microscopy and spectroscopy on thin filins of lauryl amine (LAM) and octadecane thiol (ODT) protected gold nanoparticles. We show that the zero current in the I-V curves (measure of Coulomb blockade (CB) of the nanoparticles) depends on the properties of the spacer molecule. In both the cases the gap voltage and the tunneling current at which the images are obtained are quite different which is further confirmed from the fitting performed based on the orthodox theory. The values for the capacitance and charging energy obtained from the fitting for ODT capped particles are comparable to the values obtained using spherical capacitor model. In contrast, values of these parameters were found to differ for LAM capped nanoparticles. While imaging, ODT capped nanoparticles were observed to drag along the scan direction leading to ordering of particles. Images of LAM capped gold nanoparticles show local ordering in self-assembly of particles although no evidence of large scale ordering in spatial Fourier transform was seen. These observations suggest that nanoparticles with larger CB would be intaged nonevasively in contrast to small CB systems for which tip induced effects will be dominant. In both the systems the current was found to rise faster than theoretical curves based on the orthodox theory suggesting that mechanism of charge transfer in this case may involve field emission rather than tunneling through a rectangular barrier. An attempt has been made to explain charge transfer based on Fowler-Nordheim (F-N) plots of the I-V curves. (c) 2006 Elsevier B.V All rights reserved.</p>10aNanostructures10ascanning tunneling microscopy (STM)1 aDatar, Suwarna1 aChaudhary, Minakshi, V.1 aSastry, Murali1 aDharmadhikari, C., V.  uhttps://library.ncl.res.in/content/scanning-tunneling-microscopyspectroscopy-au-nanoparticles-assembled-using-lauryl-amine-lam