Highly ordered GaAs nanodot arrays were successfully grown on GaAs (0 0 1) substrates through anodic nanochannel alumina masks using molecular beam epitaxy. These nanodot arrays replicate the hexagonal lattice pattern with period spacing of 100 nm on the nanochannel alumina mask. The dots also retain the circular shape and good size uniformity of the nanopores on the mask, and the dot size is adjustable by controlling the pore size of the mask. The selectivity of GaAs growth on the GaAs surface exposed under the nanoholes compared with GaAs deposition on the Al2O3 mask increases with reducing growth rate. This approach provides a low cost means for fabricating novel arrays of quantum nanostructures. (C) 2002 Elsevier Science B.V. All rights reserved.