TEM and X-ray diffraction studies of III-V lattice mismatched multilayers and superlattices

Transmission Electron Microscopy, High Resolution X-ray Diffraction, Rutherford Backscattering and Channeling, X-ray reciprocal lattice maps and low temperature Spectrally Resolved Cathodoluminescence have been employed for studying plastic relaxation and nucleation of extended defects in lattice mismatched InGaAs/GaAs multilayers and InGaAs/InP multi quantum wells grown under compressive and tensile conditions respectively. For InGaAs/GaAs compositionally graded structures, on the basis of the assumption that the elastic energy per unit interface area remains constant during the epilayer relaxation, the possibility of growing buffer structures with prefixed residual strain and composition is discussed in terms of misfit gradients inside the layers.