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Both crystal structure and energy band-structure changes caused by As[sup +] implantation and by subsequent annealing in GaAs and in an In[sub 0.253]Ga[sub 0.747]As quantum well are studied. We demonstrate that the main implantation impact to the crystal structure is the creation of a large number of point defects and strong compressive strain of up to -0.1%. Raman and x-ray data demonstrate almost complete structural recovery for rapid thermal annealing temperatures>=600 °C. While the lattice expansion becomes relaxed by annealing, the implantation-induced ionized point defects are still present up to the highest annealing temperatures applied. Under these circumstances, a 22 meV blueshift of the heavy-hole–electron (1hh–1e) transition within the quantum well and a substantial reduction of the nonequilibrium carrier lifetime remain as consequence of implantation. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Interactive analysis of 3D relational data is challenging. A common way of representing such data are node-link diagrams as they support analysts in achieving a mental model of the data. However, naïve 3D depictions of complex graphs tend to be visually cluttered, even more than in a 2D layout. This makes graph exploration and data analysis less efficient. This problem can be addressed by edge bundling. We introduce a 3D cluster-based edge bundling algorithm that is inspired by the force-directed edge bundling (FDEB) algorithm [HvW09b] and fulfills the requirements to be embedded in an interactive framework for spatial data analysis. It is parallelized and scales with the size of the graph regarding the runtime. Furthermore, it maintains the edge's model and thus supports rendering the graph in different structural styles. We demonstrate this with a graph originating from a simulation of the function of a macaque brain. [ABSTRACT FROM AUTHOR]

The local thermoelectric properties of a SeCl4-graphite intercalate compound (SeCl4-GIC) are studied by means of scanning-tunneling microscopy (STM). The analysis by micro-Raman spectroscopy suggested two domains, a “carbonlike” and a “SeCl4-GIC-like.” By using the thermovoltage that arises if a temperature difference between the tunneling tip and the sample of a STM is applied, areas with a difference in the local density of states can be distinguished with high lateral resolution. The differences in the local thermopower may be as large as several hundred μV/K. The aim was to estimate the contribution of the different domains to the thermopower of SeCl4-GIC. [ABSTRACT FROM AUTHOR]