Electron holography study of electric field variations.

This paper presents a review of the recent electron holography studies on electric field variation that have been carried out using multifunctional specimen holders. In addition to the standard inner potential analysis, studies on electric field variations around field emission tips have been carried out. The electric field variations caused by ballistic emission in the case of a field emitter made of a TaSi(2) nanowire have been analyzed using electron holography. The charges and electric fields in electrophotographic materials such as toner particles and organic photoconductors have been quantitatively evaluated after equipping the specimen holder with a piezodriving probe to shield the specimens from electron irradiation. The conductivity and electric field variations in the case of Ag-based conductive adhesives have been analyzed by applying an electric current through the holder. Finally, the characteristic charging effect induced by electron irradiation in biological specimens has been studied. It has also been pointed out that under certain experimental conditions, the stationary orbits of electron-induced secondary electrons can be located by electric field visualization.