Prof. Axel Hoffmann Profile

Prof. Axel Hoffmann

Professor at Technische Univ Berlin

SPIE Involvement:

Author

Publications (20)

Proceedings Article | 4 March 2019 Presentation

Presentation

Nanometer scale cathodoluminescence of GaN quantum-dots on a wavelength-matched deep-UV distributed Bragg reflector (Conference Presentation)

Hannes Schuermann, Gordon Schmidt, Christoph Berger, Sebastian Metzner, Peter Veit, Jürgen Bläsing, Frank Bertram, Armin Dadgar, André Strittmatter, Jürgen Christen, Stefan Kalinowski, Gordon Callsen, Stefan Jagsch, Markus Wagner, Axel Hoffmann

Proceedings Volume 10929, 109290A (2019) https://doi.org/10.1117/12.2510350

KEYWORDS: Vapor phase epitaxy, Gallium nitride, Deep ultraviolet, Distributed Bragg reflectors, Quantum dots, Reflectivity, Epitaxy, Single photon, Absorption, Gallium

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Proceedings Article | 14 March 2018 Presentation

Presentation

QCSE tuning in polar GaN/AlN heterostructures (Conference Presentation)

Gerald Hönig, Sarah Schlichting, Markus Wagner, Jan Müssener, Pascal Hille, Tim Grieb, Jörg Teubert, Jörg Schörmann, Andreas Rosenauer, Martin Eickhoff, Axel Hoffmann, Gordon Callsen

Proceedings Volume 10554, 105540B (2018) https://doi.org/10.1117/12.2295328

KEYWORDS: Heterojunctions, Gallium nitride, Quantum efficiency, Nanostructures, Nanowires, Excitons, Light sources

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Proceedings Article | 14 March 2018 Presentation

Presentation

Optical properties of doped GaN (Conference Presentation)

Axel Hoffmann, Christian Nenstiel, Markus Wagner, Felix Nippert, Gordon Callsen, Nadja Jankowski, Armin Dadgar, Stacia Keller

Proceedings Volume 10532, 105320M (2018) https://doi.org/10.1117/12.2293824

KEYWORDS: Gallium nitride, Phonons, Optical properties, Excitons, Germanium, Particles, Silicon, Silicon carbide, Carbon, Transition metals

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Proceedings Article | 14 March 2018 Presentation

Presentation

Carrier localization in InGaN-based light-emitting diodes (Conference Presentation)

Felix Nippert, Sergey Karpov, Markus Wagner, Gordon Callsen, Thomas Kure, Bastian Galler, Hans-Jürgen Lugauer, Martin Strassburg, Axel Hoffmann

Proceedings Volume 10554, 105540D (2018) https://doi.org/10.1117/12.2292437

KEYWORDS: Light emitting diodes, Quantum efficiency, Applied physics, Indium, Electrons, Quantum wells, Electro optics, Electroluminescence, Internal quantum efficiency, Indium gallium nitride

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Proceedings Article | 1 May 2017 Presentation

Presentation

Phononic properties of superlattices and multi quantum well heterostructures (Conference Presentation)

Markus Wagner, Juan Sebastian Reparaz, Gordon Callsen, Felix Nippert, Thomas Kure, Axel Hoffmann, Maxime Hugues, Monique Teysseire, Benjamin Damilano, Jean-Michel Chauveau

Proceedings Volume 10105, 101050P (2017) https://doi.org/10.1117/12.2253653

KEYWORDS: Current controlled current source, Phonons, Quantum wells, Superlattices, Oxides, Heterojunctions, Magnesium

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Proceedings Article | 19 April 2017 Presentation

Presentation

Direct comparison of structural and optical properties of a nitride-based core-shell microrod LED by means of highly spatially-resolved cathodoluminescence and u-Raman (Conference Presentation)

Frank Bertram, Marcus Müller, Peter Veit, Christian Nenstiel, Gordon Callsen, Matin Mohajerani, Jana Hartmann, Hao Zhou, Hergo-Heinrich Wehmann, Axel Hoffmann, Andreas Waag, Jürgen Christen

Proceedings Volume 10104, 101041V (2017) https://doi.org/10.1117/12.2251748

KEYWORDS: Scanning electron microscopy, Electron microscopes, Gallium nitride, Quantum wells, Indium gallium nitride, Scanning transmission electron microscopy, Light emitting diodes, Raman spectroscopy, Indium, Optical properties

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Proceedings Article | 2 November 2016 Presentation

Presentation

Infrared nanoscopy of In-rich InGaN epilayers (Conference Presentation)

Daniel Seidlitz, Alireza Fali, Indika Matara Kankanamge, Dorian Alden, Ramon Collazo, Axel Hoffmann, Nikolaus Dietz, Yohannes Abate

Proceedings Volume 9954, 995408 (2016) https://doi.org/10.1117/12.2238043

KEYWORDS: Indium gallium nitride, Infrared radiation, Near field scanning optical microscopy, Dielectrics, Near field optics, Heterojunctions, Infrared imaging, Spectroscopy, Imaging spectroscopy, Super resolution microscopy

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Proceedings Article | 8 March 2016 Paper

Paper

Estimation of free carrier concentrations in high-quality heavily doped GaN:Si micro-rods by photoluminescence and Raman spectroscopy

M. Mohajerani, S. Khachadorian, C. Nenstiel, T. Schimpke, A. Avramescu, M. Strassburg, A. Hoffmann, A. Waag

Proceedings Volume 9768, 976803 (2016) https://doi.org/10.1117/12.2212890

KEYWORDS: Raman spectroscopy, Gallium nitride, Doping, Light emitting diodes, Luminescence, Crystals, Sapphire, Silicon, Plasmons, Electrons

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Proceedings Article | 8 September 2015 Paper

Paper

Optoelectronic and structural properties of InGaN nanostructures grown by plasma-assisted MOCVD

Daniel Seidlitz, M. K. Senevirathna, Y. Abate, A. Hoffmann, N. Dietz

Proceedings Volume 9571, 95710P (2015) https://doi.org/10.1117/12.2188612

KEYWORDS: Plasma, Indium nitride, Indium gallium nitride, Raman spectroscopy, Nitrogen, FT-IR spectroscopy, Molybdenum, Optoelectronics, Near field scanning optical microscopy, Dielectrics

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Proceedings Article | 9 March 2015 Paper

Paper

Green (In,Ga,Al)P-GaP light-emitting diodes grown on high-index GaAs surfaces

Nikolay Ledentsov, V. Shchukin, J. Lyytikäinen, O. Okhotnikov, N. Cherkashin, Yu Shernyakov, A. Payusov, Nikita Gordeev, M. Maximov, S. Schlichting, F. Nippert, A. Hoffmann

Proceedings Volume 9383, 93830E (2015) https://doi.org/10.1117/12.2083953

KEYWORDS: Electroluminescence, Gallium arsenide, Light emitting diodes, Superlattices, Transmission electron microscopy, Cladding, Electrons, Heterojunctions, Aluminium gallium indium phosphide, Aluminum

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SPIE Journal Paper | 28 August 2013

Array of tunneling-coupled quantum dots as a terahertz range quantum nanoantenna

Yauhen Yerchak, Gregory Slepyan, Sergey Maksimenko, Axel Hoffmann, Fridrikh Bass

JNP, Vol. 7, Issue 01, 073085, (August 2013) https://doi.org/10.1117/12.10.1117/1.JNP.7.073085

KEYWORDS: Antennas, Quantum dots, Chromium, Terahertz radiation, Electromagnetism, Light wave propagation, Excitons, Phase velocity, Radio propagation, Nanoantennas

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Proceedings Article | 15 October 2012 Paper

Paper

Effect of V/III molar ratio on the structural and optical properties of InN epilayers grown by HPCVD

Ramazan Atalay, Max Buegler, Sampath Gamage, M. K. Senevirathna, Bahadir Küçükgök, Andrew Melton, Axel Hoffmann, A. G. Unil Perera, Ian Ferguson, Nikolaus Dietz

Proceedings Volume 8484, 84840X (2012) https://doi.org/10.1117/12.930199

KEYWORDS: Indium nitride, Raman spectroscopy, Phonons, FT-IR spectroscopy, Infrared spectroscopy, Optoelectronics, Crystals, X-ray diffraction, Reflectance spectroscopy, Spectroscopy

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Proceedings Article | 18 August 2010 Paper

Paper

Reactor pressure: growth temperature relation for InN epilayers grown by high-pressure CVD

M. Buegler, S. Gamage, R. Atalay, J. Wang, I. Senevirathna, R. Kirste, T. Xu, M. Jamil, I. Ferguson, J. Tweedie, R. Collazo, A. Hoffmann, Z. Sitar, N. Dietz

Proceedings Volume 7784, 77840F (2010) https://doi.org/10.1117/12.860952

KEYWORDS: Indium nitride, Chemical vapor deposition, Raman spectroscopy, Crystals, Infrared spectroscopy, Indium, Heterojunctions, Gallium nitride, Nitrogen, Sapphire

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Proceedings Article | 5 May 2010 Paper

Paper

The toolbox of fluorescence standards: flexible calibration tools for the standardization of fluorescence-based measurements

Ute Resch-Genger, K. Hoffmann, C. Würth, T. Behnke, A. Hoffmann, D. Pfeifer, A. Engel

Proceedings Volume 7666, 76661J (2010) https://doi.org/10.1117/12.853133

KEYWORDS: Luminescence, Standards development, Glasses, Calibration, Anisotropy, Solids, Absorption, Liquids, Sensors, Polymers

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Proceedings Article | 15 February 2008 Paper

Paper

Optical and structural properties of homoepitaxial ZnO

T. Bartel, M. Wagner, U. Haboeck, A. Hoffmann, C. Neumann, S. Lautenschläger, J. Sann, B. Meyer

Proceedings Volume 6895, 689502 (2008) https://doi.org/10.1117/12.775217

KEYWORDS: Zinc oxide, Raman spectroscopy, Excitons, Crystals, Luminescence, Raman scattering, Zinc, Chemical vapor deposition, Transmission electron microscopy, Oxygen

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Proceedings Article | 20 February 2007 Paper

Paper

Photonic properties of ZnO epilayers

M. Wagner, U. Haboeck, P. Zimmer, A. Hoffmann, S. Lautenschläger, C. Neumann, J. Sann, B. Meyer

Proceedings Volume 6474, 64740X (2007) https://doi.org/10.1117/12.717785

KEYWORDS: Zinc oxide, Raman spectroscopy, Excitons, Crystals, Raman scattering, Reflectance spectroscopy, Polaritons, Scattering, Luminescence, Phonons

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Proceedings Article | 25 March 2005 Paper

Paper

Multifunctional III-nitride dilute magnetic semiconductor epilayers and nanostructures as a future platform for spintronic devices

Matthew Kane, Martin Strassburg, Ali Asghar, Qing Song, Shalini Gupta, Jayantha Senawiratne, Christoph Hums, Ute Haboeck, Axel Hoffmann, Dmitry Azamat, Wolfgang Gehlhoff, Nikolaus Dietz, Z. John Zhang, Christopher Summers, Ian Ferguson

Proceedings Volume 5732, (2005) https://doi.org/10.1117/12.582980

KEYWORDS: Manganese, Gallium, Gallium nitride, Magnetism, Nanostructures, Annealing, Metalorganic chemical vapor deposition, Silicon, Magnetic semiconductors, Ferromagnetics

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Proceedings Article | 2 August 2004 Paper

Paper

Strong coupling between quantum dot and electromagnetic field: local field effects

Gregory Slepyan, Andrei Magyarov, Sergey Maksimenko, Alex Hoffmann, Dieter Bimberg

Proceedings Volume 5509, (2004) https://doi.org/10.1117/12.555830

KEYWORDS: Electromagnetism, Quantum dots, Gaussian pulse, Polarization, Excitons, Electron holes, Semiconductors, Chemical species, Spherical lenses, Particles

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Proceedings Article | 1 March 1991 Paper

Paper

Threshold current and carrier lifetime in MOVPE regrown 1.5 um GaInAsP buried ridge structure lasers

M. Tischel, M. Rosenzweig, Axel Hoffmann, Herbert Venghaus, F. Fidorra

Proceedings Volume 1361, (1991) https://doi.org/10.1117/12.24316

KEYWORDS: Laser damage threshold, Laser applications, Zinc, Optoelectronic devices, Modulation, Pulsed laser operation, Semiconductor lasers, Photonic integrated circuits, Quantum efficiency, Ions

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Proceedings Article | 1 February 1991 Paper

Paper

Nonlinear optical gain in InGaAs/InGaAsP quantum-wells

M. Rosenzweig, M. Moehrle, H. Dueser, M. Tischel, R. Heitz, Axel Hoffmann

Proceedings Volume 1362, (1991) https://doi.org/10.1117/12.24481

KEYWORDS: Optoelectronic devices, Quantum wells, Electrons, Waveguides, Physics, Semiconductor lasers, Laser damage threshold, Indium gallium arsenide, Laser applications, Semiconducting wafers

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Showing 5 of 20 publications

Conference Committee Involvement (20)

Oxide-based Materials and Devices XI

3 February 2020 | San Francisco, California, United States

Oxide-based Materials and Devices X

3 February 2019 | San Francisco, California, United States

Oxide-based Materials and Devices IX

28 January 2018 | San Francisco, California, United States

Oxide-based Materials and Devices VIII

29 January 2017 | San Francisco, California, United States

Oxide-based Materials and Devices VII

14 February 2016 | San Francisco, California, United States

Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling XII

9 February 2015 | San Francisco, California, United States

Oxide-based Materials and Devices VI

8 February 2015 | San Francisco, California, United States

Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling XI

3 February 2014 | San Francisco, California, United States

Oxide-based Materials and Devices V

2 February 2014 | San Francisco, California, United States

Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling X

4 February 2013 | San Francisco, California, United States

Oxide-based Materials and Devices IV

4 February 2013 | San Francisco, California, United States

Oxide-based Materials and Devices III

22 January 2012 | San Francisco, California, United States

Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling VIII

25 January 2011 | San Francisco, California, United States

Oxide-based Materials and Devices II

23 January 2011 | San Francisco, California, United States

Quantum Dots and Nanostructures: Synthesis, Characterization, and Modeling VII

24 January 2010 | San Francisco, California, United States

Quantum Dots, Particles, and Nanoclusters VI

25 January 2009 | San Jose, California, United States

Quantum Dots, Particles, and Nanoclusters V

21 January 2008 | San Jose, California, United States

Quantum Dots, Particles, and Nanoclusters IV

22 January 2007 | San Jose, California, United States

Quantum Dots, Particles, and Nanoclusters III

23 January 2006 | San Jose, California, United States

Quantum Dots, Nanoparticles, and Nanoclusters II

24 January 2005 | San Jose, California, United States

Showing 5 of 20 Conference Committees

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