1,721,022 research outputs found
Si/Ge intermixing and Island-Island Interaction in Ge/Si(100) Self-Assembled Islands
No full textIn this paper we present a study of the influence of the growth rate and deposition temperature on the growth dynamic of self-assembled Ge/Si(100) islands. By combining AFM and XPS measurements we show that the main effect of rising the deposition temperature is an enhancement of the Ge-Si intermixing. The actual composition of the Ge islands as a function of deposition temperature has been measured in the 450 °C- 850 °C range: the Ge content x in the alloyed epilayer was found to decrease from x=l to x=0.28. By changing the growth rate at fixed deposition temperature we were also able to modify the island density. The influence of the island density on the island size has been investigated. We found that an increase of the island density from 109 to 2×1010 cm-2 at T=600 °C brings about a change of the mean island size from 85 to 55 nm. This reduction is explained in terms of island-island interaction effects on the growth dynamic
Island and wetting-layer intermixing in the Ge/Si(001) system uponcapping
No full textIn this paper we present an atomic force microscopy and X-rayphotoemission spectroscopy study of the composition and shape evolutionof self-assembled Ge/Si(001) islands upon capping with Si. We foundthat the islands undergo a reverse Straski-Krastanov shape evolution,with a progressive Si-enrichment of both the wetting layer and theislands. We demonstrate that the island shape evolves at constantvolume with silicon atom incorporation occurring in the absence oflateral diffusion of Ge and Si atoms from the wetting layer to theislands themselves. (C) 2008 Elsevier Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Freezing shape and composition of Ge/Si(001) self-assembled islands during silicon capping
No full text- …
