Low-energy electron point source microscope with position-sensitive electron energy analyzer

A low-energy electron point source microscope equipped with a position-sens itive energy analyzer is constructed. A nanometer-sized feature can be zoom ed in and its energy-loss spectrum can be measured with a retarding field-t ype energy analyzer mounted in front of the imaging screen. The geometric a nd the electronic structures of carbon nanotubes are measured with the pres ent system. Interference between the scattered and the transmitted electron beams through the carbon nanotubes is observed using an atomically sharp f ield emitter. The electron energy-loss spectrum shows two prominent peaks a t similar to 7 and 16-17 eV, which are identified as the pi plasmon and (pi + sigma) surface-plasmon peaks. This result is consistent with the measure ments of high-energy electron energy-loss spectroscopy as well as the theor etical calculation. (C) 1999 American Institute of Physics. [S0034-6748(99) 02011-0].