@article{3888, abstract = {{We successfully developed a process to fabricate freestanding cubic aluminium nitride (c-AlN) membranes containing cubic gallium nitride (c-GaN) quantum dots (QDs). The samples were grown by plasma assisted molecular beam epitaxy (MBE). To realize the photonic crystal (PhC) membrane we have chosen a triangular array of holes. The array was fabricated by electron beam lithography and several steps of reactive ion etching (RIE) with the help of a hard mask and an undercut of the active layer. The r/a- ratio of 0.35 was deter- mined by numerical simulations to obtain a preferably wide photonic band gap. Micro-photoluminescence (μ-PL) measurements of the photonic crystals, in particular of a H1 and a L3 cavity, and the emission of the QD ensemble were performed to characterize the samples. The PhCs show high quality factors of 4400 for the H1 cavity and about 5000/3000 for two different modes of the L3 cavity, respectively. The energy of the fundamental modes is in good agreement to the numerical simulations. }}, author = {{Blumenthal, Sarah and Bürger, Matthias and Hildebrandt, Andre and Förstner, Jens and Weber, Nils and Meier, Cedrik and Reuter, Dirk and As, Donat J.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_phc, tet_topic_qd}}, number = {{5-6}}, pages = {{292--296}}, publisher = {{Wiley}}, title = {{{Fabrication and characterization of two-dimensional cubic AlN photonic crystal membranes containing zincblende GaN quantum dots}}}, doi = {{10.1002/pssc.201600010}}, volume = {{13}}, year = {{2016}}, } @article{4024, abstract = {{We investigate the formation of cubic GaN quantum dots (QDs) on pseudomorphic strained cubic AlN layers on 3C-SiC (001) substrates grown by means of molecular beam epitaxy. Surface morphologies of various QD sizes and densities were obtained from uncapped samples by atomic force microscopy. These results were correlated with similar but capped samples by photoluminescence experiments. The QD density varies by one order of magnitude from ~1x10^10 cm^-2 to ~1x10^11 cm^-2 as a function of the GaN coverage on the surface. The initial layer thickness for the creation of cubic GaN QDs on cubic AlN was obtained to 1.95 monolayers by a comparison between the experimental results and an analytical model. Our results reveal the strain-driven Stranski-Krastanov growth mode as the main formation process of the cubic GaN QDs. }}, author = {{Bürger, M. and Lindner, Jörg and Reuter, Dirk and As, D. J.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{4-5}}, pages = {{452--455}}, publisher = {{Wiley}}, title = {{{Investigation of cubic GaN quantum dots grown by the Stranski-Krastanov process}}}, doi = {{10.1002/pssc.201400132}}, volume = {{12}}, year = {{2015}}, } @article{4027, abstract = {{We report the influence of {111} stacking faults on the cathodoluminescence (CL) emission characteristics of cubic GaN (c-GaN) films and cubic GaN/AlN multiquantum wells. Transmission electron microscopy (TEM) measurements indicate that stacking faults (SFs) on the {111} planes are the predominant crystallographic defects in epitaxial films, which were grown on 3CSiC/ Si (001) substrates by plasma-assisted molecular beam epitaxy. The correlation of the SFs and the luminescence output is evidenced with a CL setup integrated in a scanning TEM (STEM). By comparing the STEM images and the simultaneously measured CL signals it is demonstrated that SFs in these films lead to a reduced CL emission intensity. Furthermore, the CL emission intensity is shown to increase with increasing film thickness and decreasing SF density. This correlation can be connected to the reduction of the full width at half maximum of X-ray diffraction rocking curves with increasing film thickness of c-GaN films.}}, author = {{Kemper, R. M. and Veit, P. and Mietze, C. and Dempewolf, A. and Wecker, T. and Bertram, F. and Christen, J. and Lindner, Jörg and As, D. J.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{4-5}}, pages = {{469--472}}, publisher = {{Wiley}}, 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}}}, doi = {{10.1002/pssc.201400154}}, volume = {{12}}, year = {{2015}}, } @article{7238, author = {{Bürger, M. and Callsen, G. and Kure, T. and Hoffmann, A. and Pawlis, A. and Reuter, Dirk and As, D. J.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{3-4}}, pages = {{790--793}}, publisher = {{Wiley}}, title = {{{Non-polar GaN quantum dots integrated into high quality cubic AlN microdisks}}}, doi = {{10.1002/pssc.201300411}}, volume = {{11}}, 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{7261, author = {{Höpfner, Henning and Fritsche, Carola and Ludwig, Arne and Ludwig, Astrid and Stromberg, Frank and Wende, Heiko and Keune, Werner and Reuter, Dirk and Wieck, Andreas D. and Gerhardt, Nils C. and Hofmann, Martin R.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{9}}, pages = {{1214--1217}}, publisher = {{Wiley}}, title = {{{Spin relaxation length in quantum dot spin LEDs}}}, doi = {{10.1002/pssc.201200689}}, volume = {{10}}, year = {{2013}}, } @article{7281, author = {{Höpfner, Henning and Fritsche, Carola and Ludwig, Arne and Ludwig, Astrid and Stromberg, Frank and Wende, Heiko and Keune, Werner and Reuter, Dirk and Wieck, Andreas D. and Gerhardt, Nils C. and Hofmann, Martin R.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{9}}, pages = {{1214--1217}}, publisher = {{Wiley}}, title = {{{Spin relaxation length in quantum dot spin LEDs}}}, doi = {{10.1002/pssc.201200689}}, volume = {{10}}, year = {{2013}}, } @article{4131, abstract = {{We report an anisotropic formation of defects in cubic GaN grown on nano-patterned 3C-SiC/Si (001) by molecular beam epitaxy. Nano-patterning of 3C-SiC/Si (001) is achieved by nanosphere lithography and a reactive ion etching process. Atomic force microscopy and scanning electron microscopy show that the selectivearea- grown cubic GaN nucleates in two structurally different domains, which most probably originate from the substrate. In adjacent domains the formation of defects, especially hexagonal inclusions, is different and leads to two different surface morphologies. The dominant phase within these domains was measured by electron backscatter diffraction. Optical properties were investigated by micro-photoluminescence and cathodoluminescence spectroscopy.}}, author = {{Kemper, R. M. and Häberlen, M. and Schupp, T. and Weinl, M. and Bürger, M. and Ruth, M. and Meier, Cedrik and Niendorf, T. and Maier, H. J. and Lischka, K. and As, D. J. and Lindner, Jörg}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{3-4}}, pages = {{1028--1031}}, publisher = {{Wiley}}, title = {{{Formation of defects in cubic GaN grown on nano-patterned 3C-SiC (001)}}}, doi = {{10.1002/pssc.201100174}}, volume = {{9}}, year = {{2012}}, } @article{13560, author = {{Hölscher, R. and Sanna, S. and Schmidt, Wolf Gero}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{6}}, pages = {{1361--1365}}, title = {{{Adsorption of OH and H at the LiNbO3(0001) surface}}}, doi = {{10.1002/pssc.201100534}}, volume = {{9}}, year = {{2012}}, } @article{4136, abstract = {{Results of atomistic simulations aimed at understanding precipitation of the highly attractive wide band gap semiconductor material silicon carbide in silicon are presented. The study involves a systematic investigation of intrinsic and carbon-related defects as well as defect combinations and defect migration by both, quantummechanical first-principles as well as empirical potential methods. Comparing formation and activation energies, ground-state structures of defects and defect combinations as well as energetically favorable agglomeration of defects are predicted. Moreover, accurate ab initio calculations unveil limitations of the analytical method based on a Tersoff-like bond order potential. A work-around is proposed in order to subsequently apply the highly efficient technique on large structures not accessible by first-principles methods. The outcome of both types of simulation provides a basic microscopic understanding of defect formation and structural evolution particularly at non-equilibrium conditions strongly deviated from the ground state as commonly found in SiC growth processes. A possible precipitation mechanism, which conforms well to experimental findings and clarifies contradictory views present in the literature is outlined.}}, author = {{Zirkelbach, F. and Stritzker, B. and Nordlund, K. and Schmidt, Wolf Gero and Rauls, E. and Lindner, Jörg K. N.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{10-11}}, pages = {{1968--1973}}, publisher = {{Wiley}}, title = {{{First-principles and empirical potential simulation study of intrinsic and carbon-related defects in silicon}}}, doi = {{10.1002/pssc.201200198}}, volume = {{9}}, year = {{2012}}, } @article{21047, author = {{Brecht, Benjamin and Eckstein, Andreas and Silberhorn, Christine}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{4}}, pages = {{1235--1238}}, title = {{{Controlling the correlations in frequency upconversion in PPLN and PPKTP waveguides}}}, doi = {{10.1002/pssc.201000872}}, volume = {{8}}, year = {{2011}}, } @article{7714, author = {{Kurtze, H. and Yakovlev, D. R. and Reuter, Dirk and Wieck, A. D. and Bayer, M.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{4}}, pages = {{1165--1168}}, publisher = {{Wiley}}, title = {{{Phonon-assisted exciton spin relaxation in (In,Ga)As/GaAs quantum dots}}}, doi = {{10.1002/pssc.201000791}}, volume = {{8}}, year = {{2011}}, } @article{7335, author = {{Krenner, Hubert J. and Völk, Stefan and Schülein, Florian J. R. and Knall, Florian and Wixforth, Achim and Reuter, Dirk and Wieck, Andreas D. and Kim, Hyochul and Truong, Tuan A. and Petroff, Pierre M.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{407--410}}, publisher = {{Wiley}}, title = {{{Surface acoustic wave controlled carrier injection into self-assembled quantum dots and quantum posts}}}, doi = {{10.1002/pssc.201100236}}, volume = {{9}}, year = {{2011}}, } @article{4142, abstract = {{This paper reports the successful reduction of tensile strain in a thin ion-beam-synthesized 3C-SiC(111) layer on silicon. Significant relaxation is achieved by creating a near-interface defect structure containing nanometric voids and dislocation loops by the implantation of He ions and subsequent thermal annealing. The structural features of this defect microstructure are investigated by transmission electron microscopy. High-resolution X-ray diffraction in a parallel beam configuration is used to quantify the strain state of the top SiC layer. Further annealing experiments were carried out in order to emulate typical process conditions for the growth of wide-bandgap semiconductors like, for example GaN. It is found that prolonged annealing at elevated temperatures leads to coarsening of the voids and to a much less efficient strain reduction. We show that this issue can be resolved by the co-implantation of oxygen to form highly thermally stable cavity/extended defect structures. The technique presented here may be useful for a variety of other thermally mismatched bulk/thin film couples as well.}}, author = {{Häberlen, Maik and Murphy, Brian and Stritzker, Bernd and Lindner, Jörg}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{3}}, pages = {{944--947}}, publisher = {{Wiley}}, title = {{{Decoupling of a strained 3C-SiC(111) thin film on silicon by He+ and O+ ion implantation}}}, doi = {{10.1002/pssc.201000342}}, volume = {{8}}, year = {{2011}}, } @article{4378, abstract = {{Using a combined all-ultra-high-vacuum process employing lateral patterning with focused ion beams and molecular beam epitaxy, site-selective growth of single (In,Ga)As quantum dots is achieved. We have embedded such a layer of intentionally positioned quantum dots in the intrinsic region of a p-i-n junction so that the quantum dots can be driven electrically. In this contribution, we will present our results on the morphological properties of the ion-beam modified surface on which the quantum dot nucleation occurs together with a characterization of the electrical and optoelectronic properties. We will demonstrate that a single, individual quantum dot can directly be electrically addressed.}}, author = {{Mehta, Minisha and Reuter, Dirk and Wieck, Andreas D. and Michaelis de Vasconcellos, Steffen and Zrenner, Artur and Meier, Cedrik}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{molecular beam epitaxy, quantum dot, site control, electroluminescence}}, number = {{4}}, pages = {{1182--1185}}, publisher = {{Wiley}}, title = {{{Electrically driven intentionally positioned single quantum dot}}}, doi = {{10.1002/pssc.201000828}}, volume = {{8}}, year = {{2011}}, } @article{40186, author = {{Eckstein, Andreas and Christ, Andreas and Mosley, Peter J. and Silberhorn, Christine}}, issn = {{1862-6351}}, journal = {{physica status solidi c}}, keywords = {{Condensed Matter Physics}}, number = {{4}}, pages = {{1216--1219}}, publisher = {{Wiley}}, title = {{{Realistic g (2) measurement of a PDC source with single photon detectors in the presence of background}}}, doi = {{10.1002/pssc.201000876}}, volume = {{8}}, year = {{2011}}, } @article{4089, abstract = {{We study the influence of the phonon environment on the electron dynamics in a doped quantum dot molecule. A non-perturbative quantumkinetic theory based on correlation expansion is used in order to describe both diagonal and off-diagonal electron-phonon couplings representing real and virtual processes with relevant acoustic phonons. We show that the relaxation is dominated by phononassisted electron tunneling between constituent quantum dots and occurs on a picosecond time scale. The dependence of the time evolution of the quantum dot occupation probabilities on the energy mismatch between the quantum dots is studied in detail.}}, author = {{Grodecka-Grad, Anna and Förstner, Jens}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_qd}}, number = {{4}}, pages = {{1125--1128}}, publisher = {{Wiley}}, title = {{{Phonon-assisted decoherence and tunneling in quantum dot molecules}}}, doi = {{10.1002/pssc.201000824}}, volume = {{8}}, year = {{2011}}, } @article{4049, abstract = {{The injection of photocurrents by femtosecond laser pulses in (110)-orientedGaAs/AlGaAs quantum wells is investigated theoretically and experimentally. The roomtemperature measurements show an oscillatory dependence of the injection current amplitude and direction on the excitation photon energy. Microscopic calculations using the semiconductor Bloch equations that are set up on the basis of k.p band structure calculations provide a detailed understanding of the experimental findings.}}, author = {{Thanh Duc, Huynh and Förstner, Jens and Meier, Torsten and Priyadarshi, Shekhar and Racu, Ana Maria and Pierz, Klaus and Siegner, Uwe and Bieler, Mark}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_qw}}, number = {{4}}, pages = {{1137--1140}}, publisher = {{Wiley}}, title = {{{Oscillatory excitation energy dependence of injection currents in GaAs/AlGaAs quantum wells}}}, doi = {{10.1002/pssc.201000831}}, volume = {{8}}, year = {{2011}}, } @article{4118, abstract = {{We numerically investigate the coupling between circular resonators and study strong light‐matter coupling of single as well as multiple circular resonators to quantum‐mechanical resonators in two dimensional model simulations. For all cases, the computed resonances of the coupled system as function of the detuning show anti‐crossings. The obtained mode splittings of coupled optical resonators are strongly depending on distance and cluster in almost degenerate eigenstates for large distances, as is known from coupled resonator optical waveguides. Vacuum Rabi splitting is observed for a quantum dot strongly coupled to eigenmodes of single perfectly cylindrical resonators. }}, author = {{Declair, S. and Meier, Torsten and Förstner, Jens}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_phc, tet_topic_microdisk}}, number = {{4}}, pages = {{1254--1257}}, publisher = {{Wiley}}, title = {{{Numerical investigation of the coupling between microdisk modes and quantum dots}}}, doi = {{10.1002/pssc.201000869}}, volume = {{8}}, year = {{2011}}, } @article{13581, author = {{Wippermann, S. and Schmidt, Wolf Gero and Bechstedt, F. and Chandola, S. and Hinrichs, K. and Gensch, M. and Esser, N. and Fleischer, K. and McGilp, J. F.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{133--136}}, title = {{{Optical anisotropy of Si(111)-(4 × 1)/(8 × 2)-In nanowires calculated fromfirst-principles}}}, doi = {{10.1002/pssc.200982413}}, volume = {{7}}, year = {{2010}}, }