(a), (b) Schematic views of the structure of the QD lattice formed by ion beam irradiation of a (Ge+SiO2)/SiO2 multilayer followed by annealing. The QD lattice is described by the basis vectors , blue dashed arrows indicate the irradiation direction. (c) STEM cross section of the film. (d), (e) GISAXS maps measured on the same film parallel and perpendicular to the irradiation plane, respectively. (f), (g) GISAXS simulations obtained using model 2, corresponding to the measured maps in panels (d), (e).