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

Abstract

/npsi/ctrl?action=rtdoc&an=12744813&lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?action=rtdoc&an=12744813&lang=fr READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Three‐Dimensional Silicon‐Germanium Nanostructures for CMOS Compatible Light Emitters and Optical Interconnects

“…Including the effect of strain, the observed PL bands at 0.916 and 0.972 eV indicate a composition of the Si 1−x Ge x transition region, which is presumably located near the bottom of the Ge/Si pyramid-like clusters, to be close to x ≈ 0.2 [30]. This conclusion is supported by recent direct analytical TEM measurements [42][43][44][45].…”

“…In contrast to MBE grown samples, CVD growth of 3D Si/SiGe NSs does not provide precise control over the Ge atomic composition, and, most likely, it produces more Si/SiGe interdiffusion at heterointerfaces [42][43][44]50]. This is well reflected in PL spectra, where no fine structure has been found (see Figure 3(d)).…”

“…The standard approach to the fabrication of a 3D Si/SiGe NS, which for most experiments discussed here is a multilayer Si/SiGe cluster system, is based on the sequential physical sputtering of Si and Ge (SiGe) in MBE or the thermal decomposition of SiH 4 and GeH 4 in CVD at a temperature in the range T = 550-650 • C. At that temperature, both a high Ge solid solubility in Si as well as strain induced SiGe interdiffusion due to the ∼4% lattice mismatch between Si and Ge are important. The MBE growth provides better control over the average SiGe cluster composition, although, because of interdiffusion during growth, the composition is not uniform within the cluster volume [42][43][44][45]. Figure 1 shows typical transmission electron micrographs (TEMs) together with a summary of analytical TEM studies confirming both the 3D geometry of the SiGe NSs and the complex atomic composition.…”

“…To summarize, buried SiGe clusters with the highest Ge composition of near 50% in the middle of the clusters are surrounded by Si, which is tensile strained above each cluster and compressed laterally between clusters to maintain a low overall strain. Each SiGe cluster consists of Si 1−x Ge x crystalline alloys with x increasing toward the cluster center [43][44][45]. Thus, despite being fully crystalline alloys, 3D Si/SiGe NSs with a high (∼50%) Ge atomic concentration exhibit significant embedded strain and compositional disorder [46].…”

High resolution STEM of quantum dots and quantum wires

“…Titchmarsh, 1989). Accordingly, only STEM-XEDS composition profile of several nanometre steps in QDs have been reported (Zhi et al, 2001;Baribeau et al, 2006). The specimen-beam interaction volume and thereby, the spatial resolution in XEDS is largely dependent on specimen thickness and the size of the electron probe.…”