Abstract
The critical thickness hc of strained InxGa1−xAs layers grown by molecular beam epitaxy on GaAs(100) substrates is determined by double‐crystal x‐ray diffraction for 0.07≤x≤0.25. The experimental results are in good agreement with critical thicknesses calculated from the energy balance model of R. People and J. C. Bean [Appl. Phys. Lett. 4 7, 322 (1985)] but differ from prior photoluminescence measurements of hc for this material. Beyond the critical thickness the transition from the strained to the relaxed state occurs more rapidly as the In concentration and hence the lattice mismatch increases.