TEM STUDY OF STACKING-FAULTS AND MISFIT DISLOCATIONS IN ZNSE GAAS EPILAYERS GROWN BY MOLECULAR-BEAM EPITAXY/

As-grown and post growth annealed pseudomorphic ZnSe epilayers grown o n GaAs (001) by molecular beam epitaxy (MBE) in a single chamber have been studied by transmission electron microscopy (TEM). The density of stacking faults in as-grown layers can be reduced by three orders of magnitude when growth is initiated on a 2x3 reconstructed surface inst ead of the usual 2x1 reconstruction. There is also a correlation betwe en the misfit dislocation configuration in post growth annealed pseudo morphic layers and the substrate reconstruction. Epilayers grown on 2x 1 reconstructed substrate are dominated by zig-zag misfit dislocations deviating from the orthogonal <110> directions while straight orthogo nal <110> misfit dislocations dominate in epilayers grown on 2x3 recon structed substrate.