Photonic crystal thin films were fabricated on glass substrates both by the controlled evaporation method and the Langmuir-Blodgett deposition of a lattice of silica spheres. Infilling of the air spaces within the structures with GaAs was achieved using trimethylgallium and arsine tinder atomic-layer-deposition conditions. The effect of infiltration on the (2+1) dimensional structure of Langmuir-Blodgett photonic crystals, as compared to the face-centred cubic structure of controlled evaporation photonic crystals, is directly investigated with respect to the observed optical properties. (C) 2008 Elsevier B.V. All rights reserved.