Self-Assembled Si1-x Ge x Dots and Islands

Photoluminescence of Ge nanocrystals self-assembled on SiO2

“…A similar NC size argument also applies to the PL of annealed samples 160 and 169. The size distribution affects the PL not only through the variation of the band gap but also through exciton localization effects [27]. Thus it appears that the instrument corrected PL emission from such Ge dots could be used in combination with theory to determine the NC size distribution.…”

Probing the composition of Ge dots and Si∕Si1−xGex island superlattices

“…2 In the Raman spectrum of Si 1−x Ge x , vibrational modes appear at approximately 500, 400, and 300 cm −1 , associated with the Si-Si, Si-Ge, and Ge-Ge lattice vibrations. The Si-Si ͑Ge-Ge͒ mode frequency decreases ͑increases͒ linearly with x, while the Si-Ge mode behavior is best represented by a fourth order polynomial.…”

“…In particular, Ge dots and Si/ Si 1−x Ge x island superlattices on ͑001͒ Si have emerged as prototypical model systems for the study of self-assembly of semiconductor nanostructures. [1][2][3] Although the nucleation, size distribution, and evolution of Ge dots and Si 1−x Ge x islands are now fairly well understood, there remain questions concerning the chemical and strain profiles within these nanostructures. A better knowledge of these properties is crucial for the exploitation of these nanostructures in quantum devices.…”

Fabrication technology of SiGe hetero-structures and their properties

“…Since there are several good reviews [204][205][206][207] concerning the Ge dot formation, some general features of the formation, which are observed in the case of gas-source MBE, are described here [208]. Fig.…”