This thesis presents the first direct observations of the 3D-shape size and electrical
properties of nanoscale filaments made possible by a new Scanning Probe Microscopy-based
tomography technique referred to as scalpel SPM. Using this innovative technology and nm-scale
observations the author achieves essential insights into the filament formation mechanisms
improves the understanding required for device optimization and experimentally observes
phenomena that had previously been only theoretically proposed.
