Photoluminescence of Ge nanostructures grown by gas source molecular beam epitaxy on silicon (1 1 8) surface

In this paper, we present a photoluminescence (PL) study of Si/Ge/SiGe/Si s tructures grown by gas source molecular beam epitaxy on an (1 1 8) undulate d surface with various Ge coverage. Nucleation and growth of Ge films is ob tained by the Stranski-Krastanov mechanism. The influence of the substrate orientation on the changeover 2D-3D growth mode is investigated. Furthermor e, we show the use of growing an SiGe wetting layer to control the uniformi ty of the Ge island size. The PL signal related to the Ge islands is found to be highly dependent of the power excitation and is observed up to room t emperature. (C) 1999 Elsevier Science B.V. All rights reserved.