Growth and microstructure of self-assembled ErAs islands in GaAs

This article concerns the microstructure of self-assembled ErAs islands emb edded in GaAs. The material is grown by molecular beam epitaxy. The nucleat ion of ErAs on GaAs occurs in an island growth mode leading to spontaneous formation of nanometer-sized islands. Several layers of ErAs islands separa ted by GaAs can be stacked on top of each other to form a superlattice. A s eries of such samples were grown with different depositions of ErAs at a gr owth temperature of 535 degrees C. The microstructure of these samples was investigated by x-ray diffraction and transmission electron microscopy. We find that initially isolated ErAs islands with a diameter of 2 nm are nucle ated. With increasing ErAs deposition, these islands branch out and form ex tended structures. The samples are coherent in growth directions for ErAs d epositions up to 1.8 monolayers. At higher ErAs depositions defects are inc orporated into the GaAs matrix. (C) 2000 American Vacuum Society. [S0734-21 1X(00)07404-7].