Energy-band diagrams and current-voltage characteristics of single-barrier tunnel structures

Energy-band diagrams of single-barrier heterostructures are calculated by solving Poisson’s equation self-consistently. The implications of these energy-band profiles for the electronic properties of a few tunnel structures of current interest are discussed. The voltage drops across the cladding layers are found to be significant, in contrast with the commonly made assumption that all of the applied voltage drops linearly across the barrier layer. Furthermore, energy-band diagrams have substantial effects upon calculated tunneling current-voltage characteristics, which are extremely sensitive to the actual shape of the barrier through which the charge carriers tunnel. It is found that, in some cases, the dominant current transport mechanisms may be quite different from those expected when band bending is neglected.