DETERMINATION OF THE LATERAL PERIODICITY OF NANOMETER QUANTUM-DOT ARRAYS BY TRIPLE-CRYSTAL DIFFRACTOMETRY

The lateral periodicity of InAs quantum dot arrays in a GaAs matrix co nsisting of submonolayer InAs films grown by molecular beam epitaxy on a terraced (001) GaAs substrate was measured in the differential rock ing curve by triple crystal diffractometry. The x-ray diffraction of t he array is described in the frame of the kinematical theory. Both the changes in the scattering factor and the tetragonal deformations due to the InAs quantum dots are taken into account. The limits of the des cription assuming an ideal array are estimated using the Laue interfer ence function. The lateral periodicity of the array along [100] is 11 nm compared with 10 nm obtained from the miscut of the sample. This id eal lateral periodicity extends along [100] over about 10 cells of the array corresponding to 0.1 mum.