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Fritz Kohlrausch Preis der Österreichischen Physikalischen Gesellschaft an Rinaldo Trotta

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Bildquelle: Robert Herbst, POINT OF VIEW (http://pov.at). ...  more of Fritz Kohlrausch Preis der Österreichischen Physikalischen Gesellschaft an Rinaldo Trotta (Titel)

Video Online: "Embedding a Single Quantum Dot into a Photonic Crystal Cavity"

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Artikel OÖNachrichten: "Rinaldo Trotta: Der 1,5-Millionen-Euro-Forscher"

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Our recent work (Nature Comm.7, 10375, 2016) on tunable entangled photons from QDs has been recently highlighted in the Laser Focus World magazine!

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Back Cover of Phys. Status Solidi A 3/2016

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Winner of Science Slam Linz and the Austrian Final in Vienna 2016: Martyna Grydlik!!!

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"Wenn es in der Physik funkt...", Artikel in der PRESSE

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Position Indication:

Content

Workgroup Schäffler
  (Group-IV epitaxy)

Beschreibung: Group Leader: Prof. Friedrich Schäffler

Publications

2016

  • Lasing from Glassy Ge Quantum Dots in Crystalline Si, M. Grydlik, F. Hackl, H. Groiss, M. Glaser, A. Halilovic, T. Fromherz, W. Jantsch, F. Schäffler, M. Brehm, ACS Photonics 3, 298 - 303 (2016) http://dx.doi.org/10.1021/acsphotonics.5b00671
  • Co-Immobilization of Proteins and DNA Origami Nanoplates to Produce High-Contrast Biomolecular Nanoarrays, R. Hager, J.R. Burns, M. J. Grydlik, A. Halilovic, T. Hasengrübler, F. Schäffler, S. Howorka, Small 12, 2877 - 2884 (2016) http://dx.doi.org/10.1002/smll.201600311

2015

  • A DNA Origami Platform for Protein Interaction Analysis, V. Motsch, R. Hager, E. Sevcsik, F. Schäffler, S. Howorka, G. Schütz, Biophys. Journal 108, 99A (2015)
  • Burgers Vector Analysis of Vertical Dislocations in Ge Crystals by Large-Angle Convergent Beam Electron Diffraction, H. Groiss, M. Glaser, A. Marzegalli, F. Isa, G. Isella, L. Miglio, F. Schäffler, Microsc. Microanal. 21, 637-645 (2015), http://dx.doi.org/10.1017/S1431927615000537
  • Photoluminescence investigation of strictly ordered Ge dots grown on pit-patterned Si substrates, Moritz Brehm1,2, Martyna Grydlik, Takeshi Tayagaki, Gregor Langer, Friedrich Schäffler and Oliver G Schmidt, Nanotechnology 26, 225202 (2015) http://dx.doi.org/10.1088/0957-4484/26/22/225202
  • Optical properties of individual site-controlled Ge quantum dots, M. Grydlik, M. Brehm, T. Tayagaki, G. Langer, O.G. Schmidt, F. Schäffler, Appl. Phys. Lett. 106, 251904 (2015) http://dx.doi.org/10.1063/1.4923188
  • Nanoimprinted superlattice photonic crystal as ultraselective solar absorber, V. Rinnerbauer, E. Lausecker, F. Schäffler, P. Reininger, G. Strasser, R. D. Geil, J. D. Joannopoulos, M. Soljacic, I. Celanovic, Optica 2, 743 – 746 (2015)
  • Single SiGe quantum dots deterministically aligned to the antinodes of a photonic crystal cavity mode, M. Schatzl, F. Hackl, T. Fromherz, F. Schäffler, IEEE Proc. 12th Int. Conf. Group IV Photonics (GFP), pp. 39-40 (2015) http://dx.doi.org/10.1109/Group4.2015.7305943

2014

  • Superlattice photonic crystal as broadband solar absorber for high temperature operation, Veronika Rinnerbauer, Yichen Shen, John D. Joannopoulos, Marin Soljačić, Friedrich Schäffler, and Ivan Celanovic, Opt. Express 22, A1896 – A1906 (2014), DOI: 10.1364/OE.22.0A1895
  • Commensurate germanium light emitters in silicon-on-insulator photonic crystal slabs, R. Jannesari, M. Schatzl, F. Hackl, M. Glaser, K. Hingerl, T. Fromherz and F. Schäffler, Opt. Express 22, 25426-25435 (2014), DOI: 10.1364/OE.22.025426
  • Real-time observation of nanoscale topological transitions in epitaxial PbTe/CdTe heterostructures, H. Groiss, I. Daruka, K. Koike, M. Yano, G. Hesser, G. Springholz, N. Zakharov, P. Werner and F. Schäffler, APL Mat. 2, 012105 (2014) DOI: 10.1063/1.4859775
  • Evolution and coarsening of Si-rich SiGe islands epitaxially grown at high temperatures on Si(0 0 1), M. Brehm, M. Grydlik, F. Schäffler, O.G. Schmidt, Microelec. Eng. 125, 22 – 27 (2014) DOI: j.mee.2013.11.002
  • Influence of composition and substrate miscut on the evolution of {105}-terminated in-plane Si1.xGex quantum wires on Si(001), H. Watzinger, M. Glaser, J.J. Zhang, I. Daruka, F. Schäffler, APL Mat. 2, 076102 (2014), DOI: 1.4886218
  • Self-assembled in-plane Ge nanowires on rib-patterned Si (1 1 10) templates, L. Du, D. Scopece, G. Springholz, F. Schäffler, G. Chen, Phys. Rev. B 90, 075308 (2014), DOI: PhysRevB.90.075308

Research Fields:

  • Molecular beam epitaxy (MBE) of group IV heterostructures
  •        
  • Kinetic and strain-driven self-organization
  •        
  • Structural, electronic, optical and spin properties of Si-based heterostructures
  •        
  • Si/Si1-x-yGexCy devices
  •        
  • Transmission-Electron Microscopy (TEM)

The research conducted in the SiGe group at the Institute for Semiconductor and Solid State Physics of the Johannes Kepler University in Linz is dedicated to Si-based semiconductor heterostructures. Their growth, structural, electrical and optical properties are investigated, and their application potential is assessed by processing them into electrical and optical devices.

The heterostructures are grown in a Si molecular beam epitaxy reactor (Riber Siva 45), which provides the matrix materials Si, Ge, C and recently also C60 fullerenes. Almost arbitrary n and p doping profiles are realized with Sb and B doping sources, respectively. Molecular beam epitaxy (MBE) is a physical epitaxial technique, where matrix and doping atoms or molecules are deposited in an ultra high vacuum (typically some 10-10mbar). Heating the substrate to moderately high temperatures (some 100°C) assures sufficiently high surface mobility of impinging atoms or molecules to form a perfect continuation of the underlying Si substrate lattice. The advantage of this conceptually very simple technique lies in its excellent control of layer thicknesses (down to single atomic layers) and layer composition (from arbitrary alloys to controlled doping in the ppb range). Compared to the CVD (chemical vapor deposition) techniques, which are widely used in industrial applications, MBE offers a much higher flexibility with respect to growth rates and temperatures. Thus, the technique is especially suitable for a fast implementation and optimization of novel layer sequences and heterostructure concepts. The versatility of MBE allows a broad spectrum of topics, e.g.:

     Self-organization phenomena for the creation of nanostructures during epitaxial growth
     Deposition of Si1-xGex and Si1-x-yGexCy quantum wells for optical and electrical investigations
     Growth of complete hetero transistors for device- and spintronics applications

Examples from each of these fields can be found on these pages, in the annual report and in our picture gallery.

For the characterization of epitaxial layers a wide variety of analytical techniques is at our disposal within the institute. Surface morphologies are examined with optical phase contrast microscopy and atomic force microscopy (AFM). Structural properties, layer compositions and interfacial morphologies of heterostructures can be determined by x-ray diffraction and reflectivity. The investigation of optical properties is conducted with a photoluminescence setup, and several Fourier-Transform spectrometers for the near and middle infrared are available. Transport measurements under high magnetic fields (up to 16T) and at cryogenic temperatures (down to 300mK) can be carried out and provide fundamental information on intrinsic electrical properties and the quality of epitaxial films. Standard techniques such as Hall measurements, a parameter analyzer for measurements of I-V and C-V characteristics or a facility for DLTS (deep level transient spectroscopy) are, of course, also implemented. Completely new paths are under pursuit with investigations of two-dimensional electron gases in strained Si channels by means of electron spin resonance (ESR).

The cleanroom of our institute offers all technological and analytical tools for the manufacturing of test devices from epitaxial Si/Si1-x-yGexCy heterostructures.It is, for example, possible to produce field effect transistors with implanted Ohmic contacts and gate electrodes with gate lengths <100nm defined by electron beam lithography. Reactive ion etching and plasma enhanced deposition of dielectric layers and poly-silicon films enable the structuring and passivation of devices. Contacts and metallization layers are deposited by means of electron beam evaporators or thermal sources. An on-wafer prober allows concomitant control and characterization of every critical process step under cleanroom conditions. For high frequency measurements of finished devices access to an S parameter analyzer for frequencies up to 75GHz is available within the technical-scientific faculty. Besides application oriented tasks, the technical installations of the cleanroom are also used for nanopatterning of substrates for subsequent selective epitaxy and for the fabrication of special structures for experiments in the mesoscopic and quantum regime.