Direct observation of alloy scattering of two-dimensional electrons in AlxGa1-xAs

We have measured the alloy scattering of two-dimensionally (2D) confined electrons in AlxGa1-xAs in the dilute Al concentration limit. Alloy scattering is independent of temperature below 4.2 K, and from its linear dependence on the Al concentration we obtain a scattering rate of 35 ns(-1) per 1% Al impurities. The alloy scattering potential determined from our data, using the Fang-Howard approximation of the wave function for the 2D electrons, is 1.13 eV. (C) 2003 American Institute of Physics.