Halbleiter-Nanostrukturen und -Quantensysteme

Prof. Jonathan Finley

Forschungsgebiet

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.

Adresse/Kontakt

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

Mitarbeiterinnen und Mitarbeiter der Arbeitsgruppe

Professorinnen und Professoren

Mitarbeiterinnen und Mitarbeiter

Lehrangebot der Arbeitsgruppe

Lehrveranstaltungen mit Beteiligung der Arbeitsgruppe

Titel und Modulzuordnung
ArtSWSDozent(en)Termine
Applied Quantum Mechanics
Zuordnung zu Modulen:
VO 2 Reinhard, F. Di, 10:00–12:00, WSI 101S
Experimentalphysik 3 in englischer Sprache
Zuordnung zu Modulen:
VO 2 Finley, J. Mo, 14:00–16:00, PH HS1
Nanofabrication and Nanoanalytics
Zuordnung zu Modulen:
VO 2 Koblmüller, G. Di, 09:30–11:00, ZEI 0001
Optische Eigenschaften von Halbleitern und deren Nanostrukturen
Zuordnung zu Modulen:
VO 2 Finley, J.
Mitwirkende: Müller, K.
Di, 14:15–16:00, WSI 101S
Photonische Quantentechnologien
Zuordnung zu Modulen:
VO 2 Kaniber, M. Do, 08:30–10:00, ZNN 0.001
Aktuelle Themen der integrierten Quanten-Photonik
Zuordnung zu Modulen:
HS 2 Kaniber, M.
Leitung/Koordination: Finley, J.
Mo, 08:30–10:00, WSI 101S
Aktuelle Themen in nanostrukturierten Materialien
Zuordnung zu Modulen:
PS 1 Finley, J. Mo, 13:15–14:00, WSI 101S
Quantenphotonische und elektronische Bauelemente
Zuordnung zu Modulen:
HS 2 Finley, J.
Mitwirkende: Müller, K.
Do, 12:15–14:00, WSI 101S
Exercise to Nanofabrication and Nanoanalytics
Zuordnung zu Modulen:
UE 1
Leitung/Koordination: Koblmüller, G.
Di, 11:00–11:45, ZEI 0001
Exercise to Semiconductor Nanofabrication and Nano-analytical Methods
Zuordnung zu Modulen:
UE 1 Koblmüller, G.
Übung zu Optische Eigenschaften von Halbleitern und deren Nanostrukturen
Zuordnung zu Modulen:
UE 1 Müller, K.
Leitung/Koordination: Finley, J.
Übung zu Photonische Quantentechnologien
Zuordnung zu Modulen:
UE 1 Kaniber, M.
FOPRA-Versuch 01: Ballistischer Transport (Flippern mit Elektronen)
Zuordnung zu Modulen:
PR 1 Finley, J.
Mitwirkende: Koblmüller, G.
FOPRA-Versuch 14: Optische Absorption
Zuordnung zu Modulen:
PR 1 Finley, J.
Mitwirkende: Müller, K.
FOPRA-Versuch 24: Feldeffekt-Transistor (MOSFET)
Zuordnung zu Modulen:
PR 1 Finley, J.
Mitwirkende: Kaniber, M.
FOPRA-Versuch 45: Optische Eigenschaften von Halbleiter-Quantenfilmen
Zuordnung zu Modulen:
PR 1 Finley, J.
Mitwirkende: Simmet, T.
Munich Physics Colloquium
Zuordnung zu Modulen:
KO 2 Finley, J. Krischer, K. Mo, 17:15–19:00
Mo, 17:15–19:00, PH HS2
sowie Termine in Gruppen

Ausgeschriebene Angebote für Abschlussarbeiten an der Arbeitsgruppe

Attaching wires to doped GaAs-AlGaAs core-multishell nanowire lasers

Semiconductor nanowires (NW) are rapidly emerging as a new generation of miniaturized on-chip coherent light sources by virtue of their unique geometry. In particular, due to the natural Fabry-Perot resonators formed by guided modes between the NW-endfacets, combined with the possibilities for direct monolithic integration on Si, NW lasers offer attractive applications in future optical interconnects and data communication.

Until now these NW lasers are driven optically, an electrical operation of the device is crucial for all applications. For this purpose, electrical contacts and a precise control of the doping profile in the device is required. The aim of this maswters thesis project is to develop appropriate process technologies to contact doped core-multishell NWs in a lying and standing geometry. This enables the characterization of the devices with respect to their electrical properties. Moreover, a comprehensive 2D-3D TCAD model of the NW laser will be implemented to simulate the electrothermal performance of the device. Adjusting the simulations to the measurement results enables the optimization of the doping profile and the heterostructure design of the NW laser. Experience in the area of clean room fabrication or TCAD modeling is a benefit, but secondary to motivation, commitment and a willingness to work as part of a team.

Applications should be sent to Prof. Finley (finley@wsi.tum.de)with c.c. to Jochen Bissinger (Jochen.Bissinger@wsi.tum.de). Please include a brief CV, a copy of your Bachelor Thesis and a transcript of your grades.

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Jonathan Finley
Characterization of doped GaAs-AlGaAs core-multishell nanowire lasers

Semiconductor nanowires (NW) are rapidly emerging as a new generation of miniaturized on-chip coherent light sources by virtue of their unique geometry. In particular, as they represent natural Fabry-Perot resonators, combined with the possibilities for direct monolithic integration on Si, NW lasers offer attractive applications in future optical interconnects and data communication.

While up to date these NW lasers are driven optically, an electrical operation of these devices is necessary for all applications. For this purpose, precise control of the doping, the development of electrical contacts, and a sophisticated mirror concept in the device are required.

The aim of this project is to explore n- and p-type doping and develop appropriate process technologies for contacting doped core-multishell NWs in different device geometries. This will allow the characterization of the devices with respect to their electrical and optoelectronic properties. Moreover, a comprehensive 2D-3D TCAD model of the NW laser will be implemented to simulate the electro-thermal performance of the device. Adjusting the simulations to the measurement results will enable the optimization of the doping profile and the heterostructure design of the NW laser. In the second part of the project, different mirror concepts will be simulated and fabricated on a freestanding NW geometry and finally characterized by optical measurements.

As a highly motivated M.Sc. student you will be closely interacting with several other student members within the Nanowire Group at the Walter Schottky Institut (WSI), and you will learn a wide scope of semiconductor-based preparation and physical characterization methods and technologies. Experience in the area of clean room fabrication or TCAD modeling are a benefit, but secondary to motivation and commitment. Applications should be sent to Jochen.Bissinger@wsi.tum.de or PD Dr. Gregor Koblmueller (Gregor.Koblmueller@wsi.tum.de). Please include your CV, a copy of your Bachelor Thesis and a transcript of your grades (Bachelor & Master).

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Gregor Koblmüller
Development of InGaAs-based nanowire lasers for Si photonics

At the Walter Schottky Institut we have recently gained great expertise in exploring nanowire (NW) lasers as the smallest possible semiconductor-based coherent light sources. One of their most promising features is that they can be also integrated onto silicon (Si) platform and thereby provide a nanoscale source for potential operation in Si photonic circuits.

An important step forward towards integration into Si photonic circuits is to control the emission wavelength of the nanowire laser in the technologically relevant spectral range of 1.3 – 1.55 um. For this reason it is necessary to develop new active gain materials in III-V based nanowire lasers, such as InGaAs multi-quantum well structures inside NW Fabry-Perot resonator cavities, and integrate these onto Si-based ridge waveguides.

The aim of this project is to develop long-wavelength InGaAs-based quantum wells incorporated in GaAs-based resonator cavities using sophisticated nanofabrication and characterization methodologies. Interacting closely with a PhD student you will be designing and synthesizing these laser structures using molecular beam epitaxy, and then characterizing their laser metrics by confocal micro-photoluminescence spectroscopy (uPL). The design and characterization may also be supported by state-of-the-art simulations of the laser gain spectrum and optical waveguiding properties. Ultimately, the InGaAs-based NW lasers should be integrated directly onto Si-ridge waveguides. Here, you will be actively exploiting various semiconductor processing techniques to fabricate the desired templates for direct monolithic integration. The coupling and lasing mode propagation between NW laser and Si waveguide will then be investigated by two-axis uPL experiments.

In this thesis, you will be closely working with several other student members in the Nanowire Group at WSI, led by PD. Dr. Gregor Koblmueller. Experience in the area of clean room fabrication or optical spectroscopy is a benefit, but secondary to motivation and commitment. Applications should be sent to Gregor.Koblmueller@wsi.tum.de or Jochen.Bissinger@wsi.tum.de. Please include your CV, a copy of your Bachelor Thesis and a transcript of your grades (Bachelor & Master).

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Gregor Koblmüller
Fabrication and electrical characterization of high-mobility nanowire field effect transistor devices

At the Walter Schottky Institute we have an ongoing research program on the growth and nano­fabrication of high mobility III-V semiconductor based heterostructure nanowire FET devices. One of the possible applications of such small devices is their integration onto CMOS-compatible silicon platform and thereby pave the way for next generation ultrascaled nanoelectronic switches in future consumer electronics.

An important step towards high mobility nanowire-FET devices is a very good understanding of the charge carrier scattering processes due to impurities, crystal phase intermixing, alloy fluctuations and surface effects among others, which limit the mean free path. Such understanding may then provide routes towards resistance-less ballistic FETs, devices which ideally occur in 1D-like conductors such as nanowires.

The goal of this project is to explore the novel InAs/InAlAs nanowire material system towards the ballistic transport regime in a temperature range between 2K and 300K. Interacting closely with a PhD student you will be designing transistor structures for direct synthesis which you will thereafter fabricate into working FET devices. Hereby, you will utilize our state-of-the-art cleanroom facilities using a variety of techniques, including optical and electron beam lithography. The FET devices should be optimized with respect to their size (nanowire diameter), carrier density and channel length in order to access regimes for ballistic transport. The nanowire-FET measurements will then be performed at a dedicated low-noise temperature-dependent electrical transport setup, and the results compared with simulations of the transmission of charge carriers in a 1D-conductor.

In this thesis, you will be closely working with several other student members in the Nanowire Group at WSI, led by PD Dr. Gregor Koblmueller. Experience in the area of clean room fabrication or (nano)electronics, as well as experience using Matlab is a benefit, but secondary to motivation and commitment. Applications should be sent to Gregor.Koblmueller@wsi.tum.de or Jonathan.Becker@wsi.tum.de . Please include your CV, a copy of your Bachelor Thesis and a transcript of your grades (Bachelor & Master).

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Gregor Koblmüller
Imaging of Neural Action Potentials by Quantum Sensors and/or Deep Learning

Our young lab is using solid state qubits to build sensors, e.g. for magnetic fields. We aim to apply them to various applications, with a particular focus on life sciences.

Most of our projects focus on microscopy methods based on magnetic resonance spectroscopy of small (sub-µm) samples.

We are seeking a MSc student to study a novel application, imaging of electric action potentials of neurons, the cells performing computation in the brain. This should involve the development of a new type of sensor, based on solid state quantum materials, smart signal processing by artificial neural networks, or a combination of both.

Techniques:

* You will learn to prepare microscopy samples of both solid state samples and cell cultures. 

* You will design an experiment to detect the weak optical signals from these samples in one of our existing microscope setups. This will involve development of advanced optics and control software.  

Depending on preference and success of the initial steps you will either

* Study fluoresent quantum materials like red fluorescent diamond and their response to external electric fields. 

* Develop signal processing protocols to enhance these signals in existing devices 

 

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Kern-, Teilchen- und Astrophysik
  • Masterarbeit Biophysik
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Friedemann Reinhard
Nuclear Magnetic Resonance Microscopy

Magnetic resonance imaging (NMR/MRI), is one of the most powerful techniques to record three-dimensional images of nearly arbitrary samples. Current standard setups, such as those found in hospitals, cannot record details smaller than 1mm.  

Our group aims to push MRI to a microscopy technique by improving its spatial resolution down to the sub-nm range, the scale of single atoms. This ambitious goal has recently become a realistic prospect by a new generation of quantum sensors for magnetic fields. They are based on the nitrogen-vacancy (NV) color defect in diamond and could detect fields as small as the NMR signal of a single molecule [1,2].

We are looking for a MSc student to develop such a magnetic resonance microscope with a resolution in the intermediate (100nm-1µm) range, higher than any conventional technique, but coarser than most of our other (nm-range) projects. 

Techniques:

* You will learn to fabricate microscale electromagnets in one of our clean rooms, and optimize our fabrication techniques for your project and others. 

* You will design a sensor chip for microscale NMR detection and upgrade software and optics of one of our setups to perform the experiment. 

* You will design, implement and analyze quantum control protocols to record microscale MRI images.

[1] T. Staudacher et al., Science 339, 561 (2013)

[2] H.J. Mamin et al., Science 339, 557 (2013)

 
geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Biophysik
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Friedemann Reinhard
Synthesis and characterization of novel 2D-materials heterostructures

Layered materials have been at the center of attention since the discovery of graphene as they hold great promise for uncovering new physical phenomena and for creating new applications. Transition metal dichalcogenides (TMDCs) are such materials systems possessing a wide range of energy bandgaps and band alignments which can be tuned by layer thickness and engineering the dielectric environment.

While most of the 2D-layered materials are harvested by simple exfoliation techniques,there is currently a huge desire to prepare these materials by scalable synthesis methods which should produce high-quality wafer-scale 2D crystals with tunable properties.

The aim of this project is to exploit chemical vapor deposition (CVD) as a scalable synthesis method to create van der Waals (vdW) bonded atomically thin TMDC crystals and heterostructures, primarily from the (Mo,W)S2 family of materials. Hereby, a wide spectrum of the synthesis parameters should be explored to tune the growth kinetics and thermodynamics leading to different crystal domain shapes, sizes and orientations on different substrates. A major goal should be the demonstration of heterostructure formation between MoS2/WS2 layers as well as their embedment into h-BN (hexagonal boron nitride) to engineer the interface properties that can host new types of high-efficiency quantum emitters. A wide range of complementary nano-analytical methods is available to further investigate the structure-property function relationships, including Raman and photoluminescence spectroscopy as well as advanced microscopy methods (SEM, He-Ion Microscopy).

In this thesis, you will be closely working with other student members active in 2D-Materials Research at the WSI. Experience in the area of clean room fabrication, chemistry, or optical spectroscopy is a benefit, but secondary to motivation and commitment. Applications should be sent directly to Gregor.Koblmueller@wsi.tum.de. Please include your CV, a copy of your Bachelor Thesis and a transcript of your grades (Bachelor & Master).

geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Gregor Koblmüller
Teaching Photons New Tricks: Mode control in monolithically integrated nanowire lasers
Reliable technologies for the monolithic integration of lasers onto silicon represent the holy grail for chip-level optical interconnects. In this context, nanowires (NW) fabricated using III−V semiconductors are of strong interest since they can be grown site-selectively on silicon using conventional epitaxial approaches. Their unique one-dimensional structure and high refractive index naturally facilitate low loss optical waveguiding and optical recirculation in the active NW region. In this versatile and ambitious project, a comprehensive 2D-3D TCAD model will be implemented to analyze a monolithically integrate NW laser on a silicon-on-insulator (SOI) substrate. The aim of this project is to design the cavity and the dielectric environment of the NW laser to control and manipulate its optical properties. Furthermore, the developed design approaches will be realized by different nanofabrication technologies and characterized by several optical measurements. Experience in the area of clean room fabrication or TCAD modeling is a benefit, but secondary to motivation and commitment. Applications should be sent to Prof. Finley (finley@wsi.tum.de) including Jochen Bissinger on c.c. (Jochen.Bissinger@wsi.tum.de). Please include your CV, a copy of your Bachelor Thesis and a transcript of your grades.
geeignet als
  • Masterarbeit Physik der kondensierten Materie
  • Masterarbeit Applied and Engineering Physics
Themensteller(in): Jonathan Finley

Abgeschlossene und laufende Abschlussarbeiten an der Arbeitsgruppe

Dynamics of spins in self-assembled quantum dots
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Jonathan Finley
Silicon Nitride Photonics using 2D Nanomaterial
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Jonathan Finley

Kondensierte Materie

Wenn Atome sich zusammen tun, wird es interessant: Grundlagenforschung an Festkörperelementen, Nanostrukturen und neuen Materialien mit überraschenden Eigenschaften treffen auf innovative Anwendungen.