@article{4052, abstract = {{In this contribution we report on the optical properties of cubic AlN/GaN asymmetric multi quantum wells (MQW) structures on 3C-SiC/Si (001) substrates grown by radio-frequency plasma-assisted molecular beam epitaxy (MBE). Scanning transmission electron microscopy (STEM) and spatially resolved cathodoluminescence (CL) at room temperature and at low temperature are used to characterize the optical properties of the cubic AlN/GaN MQW structures. An increasing CL emission intensity with increasing film thickness due to the improved crystal quality was observed. This correlation can be directly connected to the reduction of the linewidth of x-ray rocking curves with increasing film thickness of the c-GaN films. Defects like stacking faults (SFs) on the {111} planes, which also can be considered as hexagonal inclusions in the cubic crystal matrix, lead to a decrease of the CL emission intensity. With low temperature CL line scans also monolayer fluctuations of the QWs have been detected and the observed transition energies agree well with solutions calculated using a one-dimensional (1D) Schrödinger-Poisson simulator.}}, author = {{As, D.J. and Kemper, R. and Mietze, C. and Wecker, T. and Lindner, Jörg and Veit, P. and Dempewolf, A. and Bertram, F. and Christen, J.}}, issn = {{1946-4274}}, journal = {{MRS Proceedings}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{Spatially resolved optical emission of cubic GaN/AlN multi-quantum well structures}}}, doi = {{10.1557/opl.2014.944}}, volume = {{1736}}, year = {{2014}}, } @article{4053, abstract = {{A novel process for the formation of pairs of opposing metallic nanotips within linear trenches on a silicon wafer is investigated in detail. The process is based on a spreading knife technique typically used in nanosphere lithography to generate monolayers of colloidal polystyrene beads. Here it is applied to initiate self-assembly of spheres in long linear trenches acting as a template for the sphere arrangement. The optimum blade velocity to deposit the spheres selectively and densely packed in the trench depends on the trench surface fraction and can be described by a modified Dimitrov model. It is demonstrated that the spheres can be used as a shadow mask to deposit metallic nanotips in a channel, which are electrically interconnected on each side of the trench, possibly enabling the control and manipulation of nanoobjects in the channel.}}, author = {{Brassat, Katharina and Lindner, Jörg}}, issn = {{1946-4274}}, journal = {{MRS Proceedings}}, location = {{Bosten (MA)}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{A template-assisted self-organization process for the formation of a linear arrangement of pairs of metallic tips}}}, doi = {{10.1557/opl.2014.265}}, volume = {{1663}}, year = {{2014}}, } @inproceedings{4054, author = {{Brassat, Katharina and Wahle, M. and Lindner, Jörg}}, location = {{Porquerolles (France)}}, title = {{{Template-assisted self-assembly process for the formation of nanogap electrodes}}}, year = {{2014}}, } @inproceedings{4055, author = {{Brassat, Katharina and Brodehl, Christoph and Lindner, Jörg}}, location = {{San Francisco (USA)}}, title = {{{Tuning the distance between opposing metallic nanotips formed by a template assisted self-assembly process}}}, year = {{2014}}, } @inproceedings{4056, author = {{Brassat, Katharina and Brodehl, Christoph and Pauly, Johannes and Drude, Dennis and Achtelik, Jörn and Riedl, Thomas and Lindner, Jörg}}, location = {{Paderborn (Germany)}}, title = {{{Surface Patterning with Nanosphere Lithography}}}, year = {{2014}}, } @inproceedings{4057, author = {{Brassat, Katharina and Brodehl, Christoph and Wahle, M. and Lindner, Jörg}}, location = {{Boston (USA)}}, title = {{{Self-assembly for the directed self-assembly of smaller objects in a microfluidic channel}}}, year = {{2014}}, } @inproceedings{4058, author = {{Brodehl, Christoph and Greulich-Weber, Siegmund and Lindner, Jörg}}, location = {{Porquerolles (France)}}, title = {{{Double-Angle-Resolved Nanosphere Lithography}}}, year = {{2014}}, } @inproceedings{4059, author = {{Brodehl, Christoph and Greulich-Weber, Siegmund and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{Nanosphere lithography for the creation of nanoparticle arrays with tailored shape}}}, year = {{2014}}, } @inproceedings{4060, author = {{Brodehl, Christoph and Greulich-Weber, Siegmund and Lindner, Jörg}}, location = {{Boston (USA)}}, title = {{{Fabrication of Arrays of Nanoparticles with Arbitrarily Designed Shape}}}, year = {{2014}}, } @inproceedings{4061, author = {{Bürger, M. and Lindner, Jörg and Reuter, Dirk and As, D.J.}}, location = {{Lille (France)}}, title = {{{Investigation of cubic GaN quantum dots grown by the Stranski-Krastanov process}}}, year = {{2014}}, } @inproceedings{4062, author = {{Drude, Dennis and Brassat, Katharina and Brodehl, Christoph and Riedl, Thomas and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{Numerical analysis of defects in colloidal nanosphere masks}}}, year = {{2014}}, } @inproceedings{4063, author = {{Ezhova, A. and Lindner, Jörg and Muldarisnur, M. and Zentgraf, Thomas and Huber, K.}}, location = {{Porquerolles (France)}}, title = {{{Ag‐nanoparticles in PA-templates}}}, year = {{2014}}, } @inproceedings{4068, author = {{Kemper, R.M. and Kovacs, A. and Riedl, Thomas and Meertens, D. and Tillmann, K. and As, D. and Lindner, Jörg}}, location = {{Lille (France)}}, title = {{{Influence of growth area reduction on cubic GaN heteroepitaxial layer growth on 3C-SiC(001)}}}, year = {{2014}}, } @inproceedings{4069, author = {{Kemper, R.M. and Veit, P. and Mietze, C. and Dempewolf, A. and Wecker, T. and Christen, J. and As, D. and Lindner, Jörg}}, location = {{Lille (France)}}, title = {{{STEM-CL investigations on the influence of stacking faults on the optical emission of cubic GaN epilayers and cubic GaN/AlN multi-quantum wells}}}, year = {{2014}}, } @inproceedings{407, abstract = {{Automated programming aims at automatically assembling a new software artifact from existing software modules. Although automated programming was revitalized through automated software composition in the last decade, the problem cannot be considered solved. Automated software composition is widely accepted as being a planning task, but the problem is that it has very special properties that other planning problems do not have and that are commonly overseen. These properties usually imply that the composition problem cannot be solved with standard planning tools. This paper gives a brief and intuitive description of the planning problem that most approaches are based on. It points out special properties of this problem and explains why it is not adequate to solve the problem with classical planning tools as done by most existing approaches.}}, author = {{Mohr, Felix}}, booktitle = {{Proceedings of the 29th International Conference on Automated Software Engineering (ASE)}}, pages = {{ 895----898}}, title = {{{Issues of Automated Software Composition in AI Planning}}}, doi = {{10.1145/2642937.2653470}}, year = {{2014}}, } @article{4070, abstract = {{We report for the first time on the growth of cubic AlN/GaN multi‐quantum wells (MQWs) on pre‐patterned 3C‐SiC/Si (001) substrates. The sample structure consists of 10 periods of 2 nm c‐AlN barriers with a 4 nm c‐GaN layer in between, which were grown on 3C‐SiC post shaped structures by means of molecular beam epitaxy. Substrate patterning has been realized by electron beam lithography and a reactive ion etching process. The 3C‐SiC posts have a length of about 550 nm and a height of about 700 nm. (Scanning) transmission electron microscopy studies show that the morphology of the MQWs is clearly influenced by {111} stacking faults, modulating the local growth rate. Further, the growth at the edges of the surface pattern is investigated. The MQW layers cover the 90° edges by developing low‐index facets rather than by forming a conformal system of 90° angled layers. }}, author = {{Kemper, R. M. and Mietze, C. and Hiller, L. and Stauden, T. and Pezoldt, J. and Meertens, D. and Luysberg, M. and As, D. J. and Lindner, Jörg}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{265--268}}, publisher = {{Wiley}}, title = {{{Cubic GaN/AlN multi-quantum wells grown on pre-patterned 3C-SiC/Si (001)}}}, doi = {{10.1002/pssc.201300292}}, volume = {{11}}, year = {{2014}}, } @article{4072, abstract = {{This paper presents a low‐cost procedure that allows for self‐organized fabrication of periodically arranged, sub‐50 nm diameter, vertical‐sidewall GaAs nanopillars on GaAs surfaces based on nanosphere lithography, and reactive ion etching (RIE). Monodispersed polystyrene (PS) sphere double layers are deposited from a colloidal suspension on pre‐treated, hydrophilized GaAs substrates. Ni is thermally evaporated to act as a hard mask for subsequent RIE. Scanning electron microscopy reveals that the Ni nanoparticles left on the substrate after PS sphere removal have polygon‐shaped in‐plane cross‐sections corresponding to the shape of the double layer mask openings. RIE using SiCl4 at low pressure and high power density leads to the formation of vertical nanopillars with circular to oval cross‐sections, whose diameters are reduced by ∼1/3 compared to those of the Ni nanoparticles. These findings can be explained by plasma‐enhanced surface diffusion and sputtering processes during RIE. The obtained GaAs nanopillars have an average diameter of only ∼23 nm, exhibit an excellent verticality with a sidewall angle of 88.9 ± 0.4° and planar top faces, as visible in transmission electron microscopy images. }}, author = {{Riedl, Thomas and Lindner, Jörg}}, issn = {{1862-6300}}, journal = {{physica status solidi (a)}}, number = {{12}}, pages = {{2871--2877}}, publisher = {{Wiley}}, title = {{{Self-organized fabrication of periodic arrays of vertical, ultra-thin nanopillars on GaAs surfaces}}}, doi = {{10.1002/pssa.201431474}}, volume = {{211}}, year = {{2014}}, } @article{4074, abstract = {{An experimental analysis of the morphology changes of hexagonally close packed polystyrene sphere monolayers induced by annealing in air is presented. The triangular interstices between each triple of spheres, which are frequently used as nanoscale mask openings in colloidal lithography, are observed to gradually shrink in size and change in shape upon annealing. Top view scanning electron microscopy images reveal that different stages are involved in the closure of monolayer interstices at annealing temperatures in the range between 110°C and 120°C. In the early stages shrinkage of the triangular interstices is dominated by material transport to and thus shortening of their corners, in the late stages interstice area reduction via displacement of the triangle edges becomes significant. At intermediate annealing times the rate of interstice area reduction displays a maximum before a stabilized state characterized by a rounded isosceles triangular shape forms.}}, author = {{Riedl, Thomas and Strake, Matthias and Sievers, Werner and Lindner, Jörg}}, issn = {{1946-4274}}, journal = {{MRS Proceedings}}, location = {{Boston (USA)}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{Thermal Modification of Nanoscale Mask Openings in Polystyrene Sphere Layers}}}, doi = {{10.1557/opl.2014.312}}, volume = {{1663}}, year = {{2014}}, } @inproceedings{4075, abstract = {{The formation of misfit dislocations is an important issue for the performance of heteroepitaxial micro- and optoelectronic devices. We analyze three approaches that quantify the stability of misfit dislocations in axial-heteroepitaxial nanowires with respect to applicability and predictions of critical nanowire dimensions. The “nanoheteroepitaxy” approach of Zubia and Hersee proves suitable for determination of strain partitioning in the presence of an elastic mismatch. Concerning the critical thickness and diameter however the descriptions of Ertekin et al. and Glas respectively yield more reliable results, owing to the consideration of the total coherent and dislocation related energies plus the residual strain energy. In contrast to the model of Ertekin et al., which refers to infinitely long nanowires, the other two mentioned approaches allow predictions of the critical thickness of mismatched deposits on the nanowire axial face.}}, author = {{Riedl, Thomas and Lindner, Jörg}}, booktitle = {{Symposium YY – Elastic Strain Engineering for Unprecedented Materials Properties }}, location = {{Boston (USA)}}, number = {{1664}}, publisher = {{MRS Online Proceedings}}, title = {{{Comparison of Theoretical Approaches Predicting the Coherent-Semicoherent Transition in Nanoscale Axial Heterostructures}}}, doi = {{10.1557/opl.2014.325 }}, year = {{2014}}, } @article{4076, abstract = {{This contribution analyzes the reliability of strain and rotation variation determination using cross‐ as well as phase‐only correlation of experimental wide‐angle electron backscatter diffraction (EBSD) patterns. For both rotation and three‐point bending the resulting displacement gradient tensor components are examined in terms of magnitude and statistical scatter as a function of various correlation procedure parameters and signal‐to‐noise ratio. It is shown that on the one hand the Fourier filter width has a major impact on the strain results. At higher noise level a smaller filter width has to be applied for obtaining maximum precision. On the other hand, the influence of the degree of overlap of the regions of interest positioned in the patterns is less important. For both rotation and bending experiments the cross‐correlation variant yields a smaller standard deviation with respect to phase‐only correlation, in particular for elevated noise level. The difference is attributed to the stronger propagation of noise effects in the course of phase‐only correlation function calculation and fitting. In the rotation experiment a standard deviation of ∼1.0 × 10^−4, averaged over the displacement gradient tensor components, and a rotational precision of ∼1.5 × 10^−4 rad have been achieved by using optimized evaluation settings. }}, author = {{Riedl, Thomas and Wendrock, H.}}, issn = {{0232-1300}}, journal = {{Crystal Research and Technology}}, number = {{4}}, pages = {{195--203}}, publisher = {{Wiley}}, title = {{{Reliability of high-resolution electron backscatter diffraction determination of strain and rotation variations using phase-only and cross correlation}}}, doi = {{10.1002/crat.201300217}}, volume = {{49}}, year = {{2014}}, }