Conductance imaging AFM and electrical properties of carbon nanotubes

This thesis reports the development of a new method for measuring electrical of nanoscale objects, called conductance imaging atomic force microscopy (CIAFM), and reports the results of measurements performed on carbon nanotube networks and nanotube junctions.; We introduce CIAFM, a method that combines atomic force microscopy and local conductance measurements. The method is implemented by using a tuning fork as cantilever and a solid metal tip. It excels at taking large amounts of measurements at high data density, making it equally suitable to analyze transitions on the nanometer scale or large systems such as networks. The method is thoroughly characterized.; CIAFM is applied to measure the local conductances of a carbon nanotube network on the nanometer scale to characterize current paths through the network. The extent of metallic connections is investigated and found to be the principal contributor to current flow on the macroscopic scale.; Finally, we analyze the length scale of conductance decay around carbon nanotube junctions. We find indication for ballistic current and exponential decay of ballistic current over a distance of several microns.