Characterization of (In, Ga, Al) As/GaAs quantum-dot superlattice structures by high-resolution X-ray diffraction

摘要

High-resolution X-ray diffraction measurements have been performed on (In, Ga, Al) As/GaAs quantum-dot superlattice structures. We are able to observe up to 31 satellite peaks from 6 periods of a quantum-dot superlattice. Theoretical simulations of the rocking curves based on the Takagi-Taupin equations of dynamical diffraction theory Agree well with the experimental data It is found, however, that to obtain agreement between theory and experiment, The height of the quantum dot, including the wetting layer under the dot, must be used in the simulations; furthermore, The indium composition is apparently reduced from its nominal value.