Charge distribution mapping by low energy electrons

Abstract

We demonstrate how low energy electron point source microscope can be used for quantitative mapping of linear charge distribution along one-dimensional wires. Imaging of electrically biased carbon nanotube ropes suspended across two electrodes showed different charge distributions for three different experimental situations: (1) ropes having good ohmic contacts to both electrodes, (2) ropes with one good and one poor ohmic contacts, and (3) ropes with one end contacted and the other end free standing. The technique gives a linear charge density resolution below 0.1e per nanometer with a spatial resolution better than 10nm. The resolution can be further improved by the proper modification of experimental setup.