Nondestructive detection of stacking faults for optimization of CdSe/ZnSe quantum-dot structures

CdSe/ZnSe quantum structures were systematically investigated by high-resolution x-ray diffraction. The samples were grown at different growth temperatures on GaAs(001) substrates by molecular-beam epitaxy. A model is presented enabling the simulation and quantitative analysis of x-ray diffraction profiles influenced by stacking faults. This yields a fast and nondestructive method for the determination of stacking fault densities after calibration by transmission electron microscopy. A steep increase of the stacking fault density above a critical thickness was found. The critical thickness decreases with increasing growth temperature. Above this critical thickness, the amount of incorporated CdSe remains apparently constant.