Fabrication of self-organised Ge dots using self-patterned SiGe template layer

This paper describes fabrication and optical properties of Ge nanostructure s (dots or wires) grown on atomically controlled and self-patterned Si1 - x Gex template layers. All the difficulty of the process lies in the realizat ion of the pre-patterned layer which is based on the kinetic development of a step-bunching instability. A comprehensive study on the influence of gro wth kinetics on morphological features of the Si1 - xGex template layer is presented. It mainly concentrates on the quantification of correlation leng th (L), amplitude (A) and aspect ratio (A/L) of the profiles by atomic forc e microscopy (AFM) Fourier transform measurements. Results show the determi nant role of annealing and interruption time on the dot stabilisation, aspe ct ratio and optical properties. Analysis of the surface profile evolution during the subsequent deposition of Ge on the template layer shows that Ge dots are fully located on the top of the Si1 - xGex undulations. Finally we show enhanced optical properties for self-organised Ge dots deposited on t he top of a self-patterned Si1 - xGex template layer. (C) 2000 Elsevier Sci ence S.A. All rights reserved.