Charge Build-Up and Intrinsic Bistability in Resonant Tunneling

Abstract

This chapter reviews the effect of space charge build-up in the quantum well of resonant tunneling devices. Space charge build-up can be particularly important in devices with thick collector barriers and requires a modification of the viewpoint of resonant tunneling as an electrical analogue of the Fabry-Perot interferometer. In particular, space charge build-up leads to a novel hysteresis effect in the current-voltage characteristics which is termed intrinsic bistability. Some of the developments leading to the experimental realisation of intrinsic bistability and of our theoretical understanding of it are outlined. The major part of the chapter describes how measurements of the tunnel current and capacitance in a quantising magnetic field provide quantitative information about the charge build-up process and the energy relaxation of carriers in the quantum well.