Independently contacted two-dimensional electron systems in double quantum wells

Abstract

A new technique for creating independent ohmic contacts to closely spaced two‐dimensional electron systems in double quantum well (DQW) structures is described. Without use of shallow diffusion or precisely controlled etching methods, the present technique results in low‐resistance contacts which can be electrostatically switched between the two‐conducting layers. The method is demonstrated with a DQW consisting of two 200 Å GaAs quantum wells separated by a 175 Å AlGaAs barrier. A wide variety of experiments on Coulomb and tunnel‐coupled 2D electron systems is now accessible.