  Semiconductor billiards are often considered as ideal systems for studying
dynamical chaos in the quantum mechanical limit. In the traditional picture,
once the electron's mean free path, as determined by the mobility, becomes
larger than the device, disorder is negligible and electron trajectories are
shaped by specular reflection from the billiard walls alone. Experimental
insight into the electron dynamics is normally obtained by magnetoconductance
measurements. A number of recent experimental studies have shown these
measurements to be largely independent of the billiards exact shape, and highly
dependent on sample-to-sample variations in disorder. In this paper, we discuss
these more recent findings within the full historical context of work on
semiconductor billiards, and offer strong evidence that small-angle scattering
at the sub-100 nm length-scale dominates transport in these devices, with
important implications for the role these devices can play for experimental
tests of ideas in quantum chaos.

Mesoscale and Nanoscale Physics;Quantum Physics