Theoretical Basis of Electron Holography for Thick Crystals and Mean Inner Potential

Electron holography (EH) using a transmission electron microscope (TEM) is an established method for measuring the phase shift of an electron passing through a specimen. The method has been applied to various specimens such as semiconductor pn-junctions, magnetic materials, and recently polymers and biological tissues. Ordinarily, a Moellenstedt -type biprism is used to split a wave front of the electron wave into the reference wave and object wave through a specimen (off-axis EH). Interference fringes are used to measure the phase shift Δϕ of the electron wave passing through the specimen. The shift is related to the mean inner potentialMean inner potential (V0) by the following equation in non-relativistic conditions as.