@article{7491, author = {{Kröger, Philipp and Ruth, Marcel and Weber, Nils and Meier, Cedrik}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, number = {{26}}, publisher = {{AIP Publishing}}, title = {{{Carrier localization in ZnO quantum wires}}}, doi = {{10.1063/1.4731767}}, volume = {{100}}, year = {{2012}}, } @article{7492, author = {{Kampmeier, J. and Rashad, M. and Woggon, U. and Ruth, M. and Meier, Cedrik and Schikora, D. and Lischka, K. and Pawlis, A.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{15}}, publisher = {{American Physical Society (APS)}}, title = {{{Enhanced photoluminescence of colloidal nanocrystals embedded in epitaxially grown semiconductor microstructures}}}, doi = {{10.1103/physrevb.85.155405}}, volume = {{85}}, year = {{2012}}, } @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{7493, author = {{Piegdon, K. A. and Lexow, M. and Grundmeier, G. and Kitzerow, Heinz-Siegfried and Pärschke, K. and Mergel, D. and Reuter, Dirk and Wieck, A. D. and Meier, Cedrik}}, issn = {{1094-4087}}, journal = {{Optics Express}}, number = {{6}}, publisher = {{The Optical Society}}, title = {{{All-optical tunability of microdisk lasers via photo-adressable polyelectrolyte functionalization}}}, doi = {{10.1364/oe.20.006060}}, volume = {{20}}, year = {{2012}}, } @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{7495, author = {{Urbanski, Martin and Piegdon, Karoline A. and Meier, Cedrik and Kitzerow, Heinz-Siegfried}}, issn = {{0267-8292}}, journal = {{Liquid Crystals}}, number = {{4}}, pages = {{475--482}}, publisher = {{Informa UK Limited}}, title = {{{Investigations on the director field around microdisc resonators}}}, doi = {{10.1080/02678292.2011.552742}}, volume = {{38}}, year = {{2011}}, } @article{4550, abstract = {{We have integrated individual (In,Ga)As quantum dots (QDs) using site-controlled molecular beam epitaxial growth into the intrinsic region of a p-i-n junction diode. This is achieved using an in situ combination of focused ion beam prepatterning, annealing, and overgrowth, resulting in arrays of individually electrically addressable (In,Ga)As QDs with full control on the lateral position. Using microelectroluminescence spectroscopy we demonstrate that these QDs have the same optical quality as optically pumped Stranski–Krastanov QDs with random nucleation located in proximity to a doped interface. The results suggest that this technique is scalable and highly interesting for different applications in quantum devices.}}, author = {{Mehta, M. and Reuter, Dirk and Wieck, A. D. and Michaelis de Vasconcellos, S. and Zrenner, Artur and Meier, Cedrik}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, number = {{14}}, publisher = {{AIP Publishing}}, title = {{{An intentionally positioned (In,Ga)As quantum dot in a micron sized light emitting diode}}}, doi = {{10.1063/1.3488812}}, volume = {{97}}, year = {{2010}}, } @article{4551, abstract = {{An intentional positioning of optically active quantum dots using site-selective growth by a combination of molecular beam epitaxy (MBE) and focused ion beam (FIB) implantation in an all-ultra-high-vacuum (UHV) setup has been successfully demonstrated. A square array of periodic holes on GaAs substrate was fabricated with FIB of 30 keV ions followed by an in situ annealing step. Subsequently, the patterned holes were overgrown with an optimized amount of InAs in order to achieve site-selective growth of the QDs on the patterned holes. Under well-optimized conditions, a selectivity of single quantum dot growth in the patterned holes of 52% was achieved. Thereafter, carrier injection and subsequent radiative recombination from the positioned InAs/GaAs self-assembled QDs was investigated by embedding the QDs in the intrinsic part of a GaAs-based p–i–n junction device. Electroluminescence spectra taken at 77 K show interband transitions up to the fifth excited state from the QDs.}}, author = {{Mehta, Minisha and Reuter, Dirk and Melnikov, Alexander and Wieck, Andreas D. and Michaelis de Vasconcellos, Steffen and Baumgarten, Tim and Zrenner, Artur and Meier, Cedrik}}, issn = {{1386-9477}}, journal = {{Physica E: Low-dimensional Systems and Nanostructures}}, keywords = {{Molecular beam epitaxy, Focused ion beam, Self-assembled quantum dot, Electroluminescence}}, number = {{10}}, pages = {{2749--2752}}, publisher = {{Elsevier BV}}, title = {{{Intentionally positioned self-assembled InAs quantum dots in an electroluminescent p–i–n junction diode}}}, doi = {{10.1016/j.physe.2009.12.053}}, volume = {{42}}, year = {{2010}}, } @article{7494, author = {{Mehta, M. and Meier, Cedrik}}, issn = {{0013-4651}}, journal = {{Journal of The Electrochemical Society}}, number = {{2}}, publisher = {{The Electrochemical Society}}, title = {{{Controlled Etching Behavior of O-Polar and Zn-Polar ZnO Single Crystals}}}, doi = {{10.1149/1.3519999}}, volume = {{158}}, year = {{2010}}, } @article{7496, author = {{Theis, Jens and Geller, Martin and Lorke, Axel and Wiggers, Hartmut and Wieck, Andreas and Meier, Cedrik}}, issn = {{0957-4484}}, journal = {{Nanotechnology}}, number = {{45}}, publisher = {{IOP Publishing}}, title = {{{Electroluminescence from silicon nanoparticles fabricated from the gas phase}}}, doi = {{10.1088/0957-4484/21/45/455201}}, volume = {{21}}, year = {{2010}}, } @article{4125, abstract = {{We numerically investigate the behavior of Whispering Gallery Modes (WGMs) in circularly shaped resonators like microdisks, with diameters in the range of optical vacuum wavelengths. The microdisk is embedded in an uniaxial anisotropic dielectric environment. By changing the optical anisotropy, one obtains spectral tunability of the optical modes. The degree of tunability strongly depends on the radial (azimuthal) mode order M (N). As the modes approach each other spectrally, anticrossing is observed, leading to a rearrangement of the optical states.}}, author = {{Declair, S. and Meier, Cedrik and Meier, Torsten and Förstner, Jens}}, issn = {{1569-4410}}, journal = {{Photonics and Nanostructures - Fundamentals and Applications}}, keywords = {{tet_topic_microdisk}}, number = {{4}}, pages = {{273--277}}, publisher = {{Elsevier BV}}, title = {{{Anticrossing of Whispering Gallery Modes in microdisk resonators embedded in an anisotropic environment}}}, doi = {{10.1016/j.photonics.2010.03.002}}, volume = {{8}}, 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}}, } @article{7497, author = {{Mehta, M. and Ruth, M. and Piegdon, K. A. and Krix, D. and Nienhaus, H. and Meier, Cedrik}}, issn = {{1071-1023}}, journal = {{Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures}}, number = {{5}}, publisher = {{American Vacuum Society}}, title = {{{Inductively coupled plasma reactive ion etching of bulk ZnO single crystal and molecular beam epitaxy grown ZnO films}}}, doi = {{10.1116/1.3186528}}, volume = {{27}}, year = {{2009}}, } @article{7498, author = {{Lei, Wen and Notthoff, Christian and Offer, Matthias and Meier, Cedrik and Lorke, Axel and Jagadish, Chennupati and Wieck, Andreas D.}}, issn = {{0884-2914}}, journal = {{Journal of Materials Research}}, number = {{07}}, pages = {{2179--2184}}, publisher = {{Cambridge University Press (CUP)}}, title = {{{Electron energy structure of self-assembled In(Ga)As nanostructures probed by capacitance-voltage spectroscopy and one-dimensional numerical simulation}}}, doi = {{10.1557/jmr.2009.0293}}, volume = {{24}}, year = {{2009}}, } @article{7499, author = {{Huba, K. and Krix, D. and Meier, Cedrik and Nienhaus, H.}}, issn = {{0734-2101}}, journal = {{Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films}}, number = {{4}}, pages = {{889--894}}, publisher = {{American Vacuum Society}}, title = {{{Ultrathin K∕p-Si(001) Schottky diodes as detectors of chemically generated hot charge carriers}}}, doi = {{10.1116/1.3100218}}, volume = {{27}}, year = {{2009}}, } @inproceedings{4179, abstract = {{We numerically investigate Whispering Gallery Modes (WGM) in a subwavelength microdisk resonator [1] embedded in an uniaxial anisotropic liquid crystal environment. It is shown that the WGMs have anticrossing behavior when modes of different radial mode order M or azimuthal order N approach each other spectrally. }}, author = {{Förstner, Jens and Declair, S. and Meier, Cedrik and Meier, Torsten}}, booktitle = {{Theoretical and Computational Nanophotonics Tacona-Photonics}}, keywords = {{tet_topic_microdisk}}, location = {{Tacona}}, number = {{1}}, pages = {{60--62}}, title = {{{Anticrossing of Whispering Gallery Modes in Microdisk Resonators Embedded in a Liquid Crystal}}}, doi = {{10.1063/1.3253921}}, volume = {{1176}}, year = {{2009}}, } @inproceedings{4181, abstract = {{We experimentally and theoretically investigate microdisk resonators with embedded quantum dots immersed in a liquid crystal in its nematic phase, showing the tunabililty of the photonic modes via external parameters like temperature or electric field.}}, author = {{Förstner, Jens and Meier, Cedrik and Piegdon, Karoline and Declair, Stefan and Hoischen, Andreas and Urbanski, Mark and Meier, Torsten and Kitzerow, Heinz-Siegfried}}, booktitle = {{Advances in Optical Sciences Congress}}, isbn = {{9781557528735}}, keywords = {{tet_topic_microdisk}}, location = {{Honolulu, Hawaii United States}}, publisher = {{OSA Technical Digest (CD) (Optical Society of America, 2009), paper NTuC2}}, title = {{{Coupling Dynamics of Quantum Dots in a Liquid-Crystal-Tunable Microdisk Resonator}}}, doi = {{10.1364/nlo.2009.ntuc2}}, year = {{2009}}, } @inbook{7500, author = {{Meier, Cedrik and Lüttjohann, Stephan and Offer, Matthias and Wiggers, Hartmut and Lorke, Axel}}, booktitle = {{Advances in Solid State Physics}}, isbn = {{9783540858584}}, issn = {{1438-4329}}, pages = {{79--90}}, publisher = {{Springer Berlin Heidelberg}}, title = {{{Silicon Nanoparticles: Excitonic Fine Structure and Oscillator Strength}}}, doi = {{10.1007/978-3-540-85859-1_7}}, year = {{2008}}, } @inproceedings{7642, author = {{Piegdon, Karoline A. and Matthias, Heinrich and Meier, Cedrik and Kitzerow, Heinz-Siegfried}}, booktitle = {{Emerging Liquid Crystal Technologies III}}, editor = {{Chien, Liang-Chy}}, publisher = {{SPIE}}, title = {{{Tunable optical properties of photonic crystals and semiconductor microdisks using liquid crystals}}}, doi = {{10.1117/12.774194}}, year = {{2008}}, }