Dependence of critical layer thickness on strain for InxGa1−xAs/GaAs strained-layer superlattices

Various InxGa1−xAs/GaAs strained-layer superlattices have been characterized by Hall effect, ion beam channeling, and photoluminescence measurements in order to evaluate their crystalline quality. Structural characteristics (e.g., layer strains and thicknesses) were obtained from channeling or x-ray diffraction studies. The structures had strains in the alloy layers of 0.5–2.7%. Critical layer thicknesses for degradation of sample quality are in good agreement with the theoretical expression proposed by J. W. Matthews and A. E. Blakeslee J. Cryst. Growth 27, 118 (1974). Our results provide important information for design of strained-layer devices.