Electron tunneling in single- and double-barrier structures.

Abstract

The transport properties of single- and double-barrier structures are elucidated. The study makes use of a novel variant of hot-electron spectroscopy, whereby the hot-electron injector is intentionally adapted so as to be weakly coupled spatially to the structure under consideration. Experimental tunneling currents and differential conductance characteristics are presented; from these data, three different tunneling characteristics are identified, arising from nonresonant, sequential, and coherent tunneling modes. Analysis of the coherent tunneling component results in the identification of the energy levels of the quantum-well structure in question; the energy levels of such structures are determined for various applied voltages.