Tunneling and nonlinear transport in a vertically coupled GaAs/AlGaAs   double quantum wire system
  We report low-dimensional tunneling in an independently contacted vertically coupled quantum wire system. This nanostructure is fabricated in a high quality GaAs/AlGaAs parallel double quantum well heterostructure. Using a novel flip chip technique to align top and bottom split gates to form low-dimensional constrictions in each of the independently contacted quantum wells we explicitly control the subband occupation of the individual wires. In addition to the expected 2D-2D tunneling results, we have found additional tunneling features that are related to the 1D quantum wires. 
E. Bielejec, J. A. Seamons, J. L. Reno and M. P. Lilly