DETERMINATION OF IN COMPOSITION IN MOLECULAR-BEAM EPITAXY GROWN INXGA1-XAS GAAS HETEROSTRUCTURES/

We have used parallel moire patterns obtained by transmission electron microscopy (TEM) to determine the In composition in highly lattice mi smatched InxGa1-xAs/GaAs heterojunctions grown by molecular beam epita xy. The results have been compared to values obtained from high resolu tion X-ray diffraction (HRXRD) and photoluminescence. The latter metho ds provide information about the average lattice parameters while the TEM also shows the spatial variation of the lattice parameters on a fi ne scale. In addition, the average residual strain in partially relaxe d structures can be estimated from the moire patterns. Therefore, the moire pattern is regarded to be a useful tool for characterizing alloy compositions in lattice mismatched semiconductor heterostructures.