SELF-ORGANIZATION OF GERMANIUM NANOISLANDS OBTAINED IN SILICON BY MOLECULAR-BEAM EPITAXY

Nanometer germanium islands in epitaxial layers of silicon are obtaine d by molecular-beam epitaxy. The dimensions and shapes of the islands are determined in an atomic-force microscope. The photoluminescence sp ectra are found to contain lines that can be interpreted as quasidirec t optical transitions in the islands. It is concluded on the basis of optical and microprobe measurements and theoretical calculations of th e energies of electronic states that silicon is dissolved in the germa nium islands. Values of the germanium and silicon contents in the soli d solution are presented. (C) 1998 American Institute of Physics. [S00 21-3640(98)00901-3].