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Semiconductor Nanostructures and Quantum Systems

Prof. Jonathan Finley

Research Field

Our group explores a wide range of topics related to the fundamental physics of nanostructured materials and their quantum-electronic and -photonic properties. We study the unique electronic, photonic and quantum properties of materials patterned over nanometer lengthscales and explore how sub-components can be integrated together to realise entirely new materials with emergent properties. This convergence of materials-nanotechnology, quantum electronics and photonics is strongly interdisciplinary, spanning topics across the physical sciences, as well as materials science and engineering.

Address/Contact

Am Coulombwall 4/I
85748 Garching b. München
+49 89 289 12771
Fax: +49 89 289 12704

Members of the Research Group

Professor

Office

Scientists

Students

Other Staff

Teaching

Course with Participations of Group Members

Titel und Modulzuordnung
ArtSWSDozent(en)Termine
Experimentalphysik 2
eLearning-Kurs aktuelle Informationen
Zuordnung zu Modulen:
VO 4 Finley, J. Mo, 08:30–10:00, MI HS1
Mi, 14:30–16:00, MI HS1
Mathematische Ergänzungen zur Experimentalphysik 2
eLearning-Kurs
Zuordnung zu Modulen:
VO 2 Höffer von Loewenfeld, P.
Leitung/Koordination: Finley, J.
Mi, 12:15–14:00, PH HS1
Offenes Tutorium zu Experimentalphysik 2
Zuordnung zu Modulen:
UE 2 Höffer von Loewenfeld, P. Rohr, C.
Leitung/Koordination: Finley, J.
Di, 12:00–14:00, ZEI 0001
Di, 12:00–14:00, GALILEO Taurus 1
Übung zu Experimentalphysik 2
eLearning-Kurs aktuelle Informationen
Zuordnung zu Modulen:
UE 2 Rohr, C.
Leitung/Koordination: Finley, J.
Termine in Gruppen
Dozentensprechstunde zu Mathematische Ergänzungen zur Experimentalphysik 2
Diese Lehrveranstaltung ist keinem Modul zugeordnet.
KO 2 Höffer von Loewenfeld, P.
Leitung/Koordination: Finley, J.

Offers for Theses in the Group

Electron Spin Qubits in Quantum Dot Molecules - Towards a Quantum Repeater

 

Quantum communication using single photons provides one route towards physically secure data transmission. However, the total length of today’s quantum key distribution systems is limited to about ~300km due to photon absorption in the “quantum channel” - typically an optical fiber. To overcome this problem, one can build so-called “quantum repeaters” in which the channel is broken down into shorter segments connected by quantum links. In our group we are working towards building a quantum repeater using optically active semiconductor-based quantum dot molecules.  We aim to make use of trapped pairs of charges – singlet-triplet (S-T) spin qubits.

In the first part of this MSc. project you fabricate a quantum photodiode structure containing coupled quantum dots. This will involve clean-room fabrication, as well as electrical characterization of the fabricated diodes. In the second part, your focus will be on optical characterization of the S-T spin qubits. The goal is to measure exceedingly long coherence times (>>1µs) for special electric fields where the energy gap of the qubit is insensitive to electric and magnetic field fluctuations.

Prior knowledge in optics, clean-room fabrication and programming are helpful – but secondary to high motivation and an open and curious mindset to tackle challenging problems. You will get experience in state-of-the-art nanofabrication, optical spectroscopy at cryogenic temperatures, as well as understanding of semiconductors in the context of quantum information and technology.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
  • Master’s Thesis Biomedical Engineering and Medical Physics
  • Master’s Thesis Matter to Life
  • Master’s Thesis Quantum Science & Technology
  • Master’s Thesis Theoretical and Mathematical Physics
Supervisor: Jonathan Finley
Electrically driven nanowire lasers as future light source for silicon photonics

Topic:

III-V semiconductor nanowire lasers combine the superior optical properties of the established III-V materials with the possibility of a site-selective and monolithic integration on a common silicon-on-insulator platform. Their recent integration on silicon waveguides marked a crucial milestone towards their usage as coherent light sources for future silicon photonics applications. However, so far pumping of nanowire lasers is done opticallywhile electrical injection is crucial for a useful application as on-chip light source.

The goal of this M.Sc. project is the realization of standing nanowire lasers on a silicon platform and the characterization of their electrical and electro-optical properties. Hereby, you will be closely working together with a PhD student. Your work will be settled over the whole fabrication process line from the first design of sophisticated nanowire heterostructures over their fabrication further to their analysis. The design will be guided by simulations for optimized laser cavity properties as well as electronic simulations of the doped heterostructures. Nanowire lasers should then be realized on lithographically patterned substrates by various bottom-up/top-down nanofabrication processes, including state-of-the-art processing in cleanroom environment. From electrical and optical characterization of the wires you should derive correlations between heterostructure design, electronic properties, contact behavior and electroluminescence to drive the optical emission properties of the nanowires into the lasing regime.

Requirements

Experience in the area of clean room fabrication and nanoanalytics as well as experience in simulations would be beneficial. Furthermore, some data analysis skills would be good:

·     Python or MATLAB

·     Origin

·     MS Office

Nevertheless, the most important requirements are motivation and commitment.  

What you will gain and learn

·     Advanced clean room processes for state-of-the-art 3D structured nanowires

·     Nanoanalytics and imaging techniques (SEM, AFM)

·     Expertise in measurements of electrical and optical properties of nanowire heterostructures (Low-noise I-V characterization, Photo- & Electroluminescence spectroscopy)


In summary, you are going to develop hands-on experience on a substantial pool of nanofabrication and -analytics methodologies available at WSI/ZNN, while contributing to a technologically and scientifically extremely relevant topic in integrated photonics. Additionally, you will get the chance to work in a top semiconductor research institute with a productive working atmosphere and a great team spirit.

Application

If you are interested in this topic or if you have any questions please send a mail to tobias.schreitmueller@wsi.tum.de or gregor.koblmueller@wsi.tum.de. Please include your CV, transcript of records and your Bachelor’s Thesis.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Gregor Koblmüller

Current and Finished Theses in the Group

InGaAs Multiquantumwell Lasers Integrated on Silicon Waveguides
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Gregor Koblmüller
NV-based nuclear magnetic resonance microscopy on the micron scale
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Friedemann Reinhard
Quantum Emitters in Two-dimensional Materials
Abschlussarbeit im Masterstudiengang Physik (Physik der kondensierten Materie)
Themensteller(in): Jonathan Finley
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