Abstract
(AlAs)0.5(GaAs)0.5 fractional‐layer superlattices with a new periodicity perpendicular to the growth direction was successfully grown by metalorganic chemical vapor deposition on (001) GaAs substrates slightly misoriented toward [110]. The atomic structures were analyzed by x‐ray superlattice satellite diffraction. Superlattice periods were exactly the same as the mean distance of each atomic step on the (001) vicinal surface. The results indicate that lateral growth from nucleation at the step edge is the dominant process compared with the two‐dimensional nucleation on atomically flat terraces.