WANNIER-STARK RESONANCES IN ZENER TUNNELING DIODES WITH GAAS ALAS SUPERLATTICES/

We present DC transport measurements of the valence to conduction band (Zener) tunneling current in a p-i-n diode with an ultrathin intrinsi c layer containing a (GaAs)(5)/(AlAs)(2) multi-quantum well structure. According to recent theoretical predictions, the DC current should sh ow maxims as a function of the reverse bias voltage that reflect the f ormation of Wannier-Stark resonances. So far, Wannier-Stark resonances have only been observed optically and never in a regime of strong Zen er tunneling. Experimentally, we find the second derivative of the cur rent-voltage characteristics to show a weak oscillatory structure inde ed, indicating the existence of Wannier-Stark resonances in Zener tunn eling. (C) 1996 Academic Press Limited