We fabricated III-V nano- and microtubes by using the bending of ultra-thin strained films by releasing them due to selective wet-chemical etching of a sacrificial layer from the substrate. The curvature is obtained by a new mechanical equilibrium shape for which the elastic strain energy of the layer-system is minimal. The resulting diameter of these tubes depends on the layer composition, layer thickness, substrate orientation and rolling direction. We studied the influence of thickness variations on the surface due to multiatomic steps on the structural properties of BGaAs/InGaAs-tubes grown on (110)-oriented GaAs-substrates. Cross-sectional transmission electron microscopy (TEM)-images on the rolled structures showed, that the large difference of the outer and inner diameter depends on the multiatomic steps at the surface of the layer-system. We also present a new material-system for the fabrication of rolled-up nanotubes (RUNTs): BGaP/InGaP with AlGaP sacrificial layer on (110)-oriented GaP-substrate. The tube diameter and the internal strain in the rolled and unrolled multilayer systems were modeled using continuum strain theory. (c) 2006 Elsevier B.V. All rights reserved.