Comment on Electron Scattering in the Image Potential Well

Abstract
Comments are made on the model of electron injection into SiO2 proposed by Berglund and Powell. Their assumptions on electron scattering, disregarding the change of the escape cone with the distance from the emitter, lead to serious underestimation of the injected current. Two alternative models of electron injection, based solely on elastic scattering are discussed and do not predict the experimental results. We suggest that observed field dependence of the injected current into SiO2 indicates that energy relaxation associated with the injected electrons is responsible for the voltage dependence of the current.