@article{36804, author = {{Henksmeier, Tobias and Schulz, Johann Friedemann and Kluth, Elias and Feneberg, Martin and Goldhahn, Rüdiger and Sanchez, Ana M. and Voigt, Markus and Grundmeier, Guido and Reuter, Dirk}}, journal = {{Journal of Crystal Growth}}, publisher = {{Elsevier}}, title = {{{Remote epitaxy of In(x)Ga(1-x)As(001) on graphene covered GaAs(001) substrates}}}, doi = {{10.1016/j.jcrysgro.2022.126756}}, volume = {{593}}, year = {{2022}}, } @misc{40428, author = {{Jonas, Björn and Heinze, Dirk Florian and Schöll, Eva and Kallert, Patricia and Langer, Timo and Krehs, Sebastian and Widhalm, Alex and Jöns, Klaus and Reuter, Dirk and Zrenner, Artur}}, publisher = {{LibreCat University}}, title = {{{Nonlinear down-conversion in a single quantum dot}}}, doi = {{10.5281/ZENODO.6024228}}, year = {{2022}}, } @inproceedings{4413, author = {{Riedl, Thomas and Kunnathully, Vinay and Trapp, Alexander and Reuter, Dirk and Lindner, Jörg}}, location = {{Sendai (Japan)}}, title = {{{Strain Relaxation in InAs Nanoislands on top of GaAs (111) A Nanopillars}}}, year = {{2018}}, } @inproceedings{4414, author = {{Riedl, Thomas and Kunnathully, Vinay and Trapp, Alexander and Reuter, Dirk and Lindner, Jörg}}, location = {{Sendai (Japan)}}, title = {{{MBE Growth of InAs on Nanopillar-Patterned GaAs (111) A }}}, year = {{2018}}, } @inproceedings{3955, author = {{Kunnathully, Vinay and Riedl, Thomas and Karlisch, A. and Reuter, Dirk and Lindner, Jörg}}, location = {{Warsaw (Poland)}}, title = {{{InAs heteroepitaxy on GaAs patterned by nanosphere lithography}}}, year = {{2017}}, } @inproceedings{3987, author = {{Riedl, Thomas and Kunnathully, Vinay and Karlisch, A. and Reuter, Dirk and Lindner, Jörg}}, location = {{Warsaq (Poland)}}, title = {{{Group III arsenide heteroepitaxy on Si(111) using SiNx nanohole masks patterned by nanosphere lithography}}}, year = {{2017}}, } @inproceedings{3988, author = {{Riedl, Thomas and Kunnathully, Vinay and Karlisch, A. and Reuter, Dirk and Weber, N. and Meier, Cedrik and Schierholz, R. and Lindner, Jörg}}, location = {{Straßburg (France)}}, title = {{{Morphology, structure and enhanced PL of molecular beam epitaxial In0.2Ga0.8As layers on nanopillar patterned GaAs}}}, year = {{2017}}, } @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{4246, abstract = {{Spins in semiconductor quantum dots have been considered as prospective quantum bit excitations. Their coupling to the crystal environment manifests itself in a limitation of the spin coherence times to the microsecond range, both for electron and hole spins. This rather short-lived coherence compared to atomic states asks for manipulations on timescales as short as possible. Due to the huge dipole moment for transitions between the valence and conduction band, pulsed laser systems offer the possibility to perform manipulations within picoseconds or even faster. Here, we report on results that show the potential of optical spin manipulations with currently available pulsed laser systems. Using picosecond laser pulses, we demonstrate optically induced spin rotations of electron and hole spins. We further realize the optical decoupling of the hole spins from the nuclear surrounding at the nanosecond timescales and demonstrate an all-optical spin tomography for interacting electron spin sub-ensembles.}}, author = {{Varwig, S. and Evers, E. and Greilich, A. and Yakovlev, D. R. and Reuter, Dirk and Wieck, A. D. and Meier, Torsten and Zrenner, Artur and Bayer, M.}}, issn = {{0946-2171}}, journal = {{Applied Physics B}}, keywords = {{Spin Polarization, Pump Pulse, Trion, Spin Component, Coherence Time}}, number = {{1}}, publisher = {{Springer Nature}}, title = {{{Advanced optical manipulation of carrier spins in (In,Ga)As quantum dots}}}, doi = {{10.1007/s00340-015-6274-y}}, volume = {{122}}, year = {{2016}}, } @article{3900, abstract = {{The coherent state preparation and control of single quantum systems is an important prerequisite for the implementation of functional quantum devices. Prominent examples for such systems are semiconductor quantum dots, which exhibit a fine structure split single exciton state and a V-type three level structure, given by a common ground state and two distinguishable and separately excitable transitions. In this work we introduce a novel concept for the preparation of a robust inversion by the sequential excitation in a V-type system via distinguishable paths.}}, author = {{Mantei, D. and Förstner, Jens and Gordon, S. and Leier, Y. A. and Rai, A. K. and Reuter, Dirk and Wieck, A. D. and Zrenner, Artur}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, keywords = {{tet_topic_qd}}, number = {{1}}, pages = {{10313}}, publisher = {{Springer Nature}}, title = {{{Robust Population Inversion by Polarization Selective Pulsed Excitation}}}, doi = {{10.1038/srep10313}}, volume = {{5}}, year = {{2015}}, } @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}}, } @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}}, } @article{3963, abstract = {{Whispering gallery modes (WGMs) were observed in 60 nm thin cubic AlN microdisk resonators containing a single layer of non-polar cubic GaN quantum dots. Freestanding microdisks were patterned by means of electron beam lithography and a two step reactive ion etching process. Micro-photoluminescence spectroscopy investigations were performed for optical characterization. We analyzed the mode spacing for disk diameters ranging from 2-4 lm. Numerical investigations using three dimensional finite difference time domain calculations were in good agreement with the experimental data. Whispering gallery modes of the radial orders 1 and 2 were identified by means of simulated mode field distributions.}}, author = {{Bürger, M. and Ruth, M. and Declair, S. and Förstner, Jens and Meier, Cedrik and As, Donat Josef}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, keywords = {{tet_topic_qd, tet_topic_microdisk}}, number = {{8}}, pages = {{081105}}, publisher = {{AIP Publishing}}, title = {{{Whispering gallery modes in zinc-blende AlN microdisks containing non-polar GaN quantum dots}}}, doi = {{10.1063/1.4793653}}, volume = {{102}}, year = {{2013}}, } @article{13568, author = {{Mietze, C. and Landmann, M. and Rauls, E. and Machhadani, H. and Sakr, S. and Tchernycheva, M. and Julien, F. H. and Schmidt, Wolf Gero and Lischka, K. and As, Donat Josef}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{19}}, title = {{{Band offsets in cubic GaN/AlN superlattices}}}, doi = {{10.1103/physrevb.83.195301}}, volume = {{83}}, year = {{2011}}, } @article{13835, author = {{Scholle, A. and Greulich-Weber, S. and As, Donat Josef and Mietze, Ch. and Son, N. T. and Hemmingsson, C. and Monemar, B. and Janzén, E. and Gerstmann, Uwe and Sanna, S. and Rauls, E. and Schmidt, Wolf Gero}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, number = {{7}}, pages = {{1728--1731}}, title = {{{Magnetic characterization of conductance electrons in GaN}}}, doi = {{10.1002/pssb.200983582}}, volume = {{247}}, year = {{2010}}, } @article{4123, abstract = {{GaAs-based semiconductor microdisks with high quality whispering gallery modes (Q44000) have been fabricated.A layer of self-organized InAs quantumdots (QDs) served as a light source to feed the optical modes at room temperature. In order to achieve frequency tuning of the optical modes, the microdisk devices have been immersed in 4 – cyano – 4´-pentylbiphenyl (5CB), a liquid crystal(LC) with a nematic phase below the clearing temperature of TC≈34°C .We have studied the device performance in the temperature rangeof T=20-50°C, in order to investigate the influence of the nematic–isotropic phase transition on the optical modes. Moreover,we havea pplied an AC electric field to the device,which leads in the nematic phase to a reorientation of the anisotropic dielectric tensor of the liquid crystal.This electrical anisotropy can be used to achieve electrical tunability of the optical modes.Using the finite-difference time domain (FDTD) technique with an anisotropic material model, we are able to describe the influence of the liquid crystal qualitatively.}}, author = {{Piegdon, Karoline A. and Offer, Matthias and Lorke, Axel and Urbanski, Martin and Hoischen, Andreas and Kitzerow, Heinz-Siegfried and Declair, Stefan and Förstner, Jens and Meier, Torsten and Reuter, Dirk and Wieck, Andreas D. and Meier, Cedrik}}, issn = {{1386-9477}}, journal = {{Physica E: Low-dimensional Systems and Nanostructures}}, keywords = {{tet_topic_qd, tet_topic_microdisk}}, number = {{10}}, pages = {{2552--2555}}, publisher = {{Elsevier BV}}, title = {{{Self-assembled quantum dots in a liquid-crystal-tunable microdisk resonator}}}, doi = {{10.1016/j.physe.2009.12.051}}, volume = {{42}}, year = {{2010}}, } @article{4172, abstract = {{Microdisks made from GaAs with embedded InAs quantum dots are immersed in the liquid crystal 4-cyano-4’-pentylbiphenyl (5CB). The quantum dots serve as emitters feeding the optical modes of the photonic cavity. By changing temperature, the liquid crystal undergoes a phase transition from the isotropic to the nematic state, which can be used as an effective tuning mechanism of the photonic modes of the cavity. In the nematic state, the uniaxial electrical anisotropy of the liquid crystal molecules can be exploited for orienting the material in an electric field, thus externally controlling the birefringence of the material. Using this effect, an electric field induced tuning of the modes is achieved. Numerical simulations using the finite-differences time-domain (FDTD) technique employing an anisotropic dielectric medium allow to understand the alignment of the liquid crystal molecules on the surface of the microdisk resonator.}}, author = {{Piegdon, Karoline A. and Declair, Stefan and Förstner, Jens and Meier, Torsten and Matthias, Heiner and Urbanski, Martin and Kitzerow, Heinz-Siegfried and Reuter, Dirk and Wieck, Andreas D. and Lorke, Axel and Meier, Cedrik}}, issn = {{1094-4087}}, journal = {{Optics Express}}, keywords = {{tet_topic_qd, tet_topic_microdisk}}, number = {{8}}, publisher = {{The Optical Society}}, title = {{{Tuning quantum-dot based photonic devices with liquid crystals}}}, doi = {{10.1364/oe.18.007946}}, volume = {{18}}, year = {{2010}}, } @inproceedings{4218, abstract = {{In this work we focus on the fabrication of ohmic contacts and of Schottky barrier devices (SBD) on non-polar cubic GaN epilayers grown by molecular beam epitaxy (MBE). A Ti/Al/Ni/Au metallization was used for ohmic contacts and the contact resistance was measured by transmission line measurements (TLM). Ni, Pd, Ag and NiSi Schottky barrier devices 300 µm in diameter were fabricated by thermal evaporation using contact lithography on cubic GaN epilayers. The current-voltage (I-V) and the capacity-voltage (C-V) characteristics were studied at room temperature in detail. A clear rectifying behavior was measured in all SBDs. In the Ni and Ag SBDs an abnormal large leakage current under reverse bias was observed. Isochronal thermal annealing of these Ni and Ag based SBDs at 200°C in air improved the reverse characteristics by up to three orders of magnitude. This is in contrast to the Pd contacts, where the as grown contact showed already good performance and thermal annealing had nearly no influence on the I-V characteristics. For all SBDs the magnitude of the reverse current is generally larger than that expected due to thermionic emission and an exponential increase of the reverse current is observed with increasing reverse voltage. In-depth analysis of the I-V characteristic showed that a thin surface barrier is formed at the metal semiconductor interface and that crystal defects like dislocations may be the reasons for the discrepancy between experimental data and thermionic emission theory. }}, author = {{As, Donat J. and Tschumak, Elena and Laubenstein, Irina and Kemper, Ricarda M. and Lischka, Klaus}}, booktitle = {{Materials Research Society Symposium Proceedings}}, pages = {{3--8}}, publisher = {{Materials Research Society}}, title = {{{Schottky and Ohmic Contacts on Non-Polar Cubic GaN Epilayers}}}, doi = {{10.1557/proc-1108-a01-02}}, volume = {{1108}}, year = {{2009}}, }