Published 1969 · Physics
This chapter discusses two theoretical models for interband tunneling in semiconducting pn junctions, the Zener field-emission model and the Fredkin-Wanner junction potential model. In Chapter 5 of this volume Esaki reviewed the main experimental facts and mentioned these two types of theory. I want to further contrast the two theoretical pictures and to emphasize two mathematical effects where the models seem to differ. These are the so-called Stark ladder and the band-edge breakdown of the WKB connection formula. Both are still somewhat controversial and of current research interest. I do not propose to explain specific calculations or to consider tunneling “assisted” by entities such as phonons, photons, or localized states.