Resonant tunneling across and mobility modulation along surface‐structured quantum wells

We present results of fabrication and transport measurements on surface‐structured quantum wells. The structures are fabricated on GaAs/AlGaAs modulation‐doped layers. Three different devices are examined: the grid‐gate lateral‐surface‐superlattice, the planar‐resonant‐tunneling field‐effect transistor, and the multiple parallel quantum wires. In the first two structures, transport is perpendicular to the field‐induced potential barriers. At 4.2 K, we observed evidence for resonant tunneling in both types of devices. In the third type of structure, transport is through isolated quantum wires parallel to the barriers. The presence of one‐dimensional energy subbands, and mobility modulation, above and below the two‐dimensional value, were observed.