Convergent beam electron diffraction study of lattice distortion in InGaAs/GaAs strained-layer superlattices grown by metalorganic chemical vapor deposition

Abstract

The intensities of sidebands in convergent beam electron diffraction reflections from plan-view specimens of strain modulated InGaAs/GaAs superlattices are dependent on the natural lattice mismatch, the ratio of the thicknesses of the superlattice layers, the period (sum of layer thicknesses) of the superlattice, and the g vectors of the reflections. The intensities of kinematic higher-order Laue zone (HOLZ) reflections have been calculated from a simple model based on alternate contraction and expansion of lattice spacings of the superlattice layers. An accurate estimate of the In content of InGaAs can be deduced from the elastic strains in the superlattice layers so obtained.