RESONANT INTERBAND TUNNELING IN INSB ELECTRON INVERSION-LAYERS

We investigate resonant interband tunnelling in asymmetrical double-ba rrier devices. The electrodes consist of degenerate p-type bulk InSb a nd the low-work-function metal Yb. A two-dimensional electron inversio n well is separated from the bulk by a bandgap barrier and from the me tal by a thin oxide barrier. Current peaks at forward biases and disti nct structures in the reverse current-voltage characteristic at 4.2 K are explained in terms of transverse wavevector conservation in tunnel ling from the electron subbands into the valence band and vice versa. Concerning the bias position of the current peaks in the forward chara cteristic the role of wavevector conservation is proved quantitatively by measurements under quantizing magnetic fields. In the NDC region c urrent peak-to-valley ratios up to 7.4 at 4.2 K and 2.0 at 77 K are ac hieved.