We report the realization of a modulation-doped quasi-three-dimensional electron system. The structure consists of a 2000-Å-wide undoped Al xGa1-xAs well bounded by undoped (spacer) and doped layers of AlyGa1-yAs (y>x) on both sides. The alloy composition in the well (x) is varied quadratically so that the combined potentials due to the AlxGa1-xAs and the electric charge in the well produce a square potential well with a nearly uniform carrier density. Magnetotransport data reveal that the system contains ≅2.5×1011 cm-2 electrons, which occupy four electric subbands and have a low-temperature mobility in excess of 1×105 cm2/V s indicating the high quality of the structure.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)