We discuss the development and optimization of lateral composition modulation in GaAsSb multilayer structures. Multilayers of this material system must be grown in strain balance with respect to the substrate in order to maintain regular composition modulation. By adjusting the thickness of each layer within the multilayer structure, the formation of lateral composition modulation can be optimized. Reducing the thickness of individual layers to 1.5 ML results in robust lateral composition modulation. However, upon further reduction to I ML, film quality degrades as anion exchange acts to cause intermixing. (c) 2005 Elsevier B.V. All rights reserved.