Inst. Festkörperphysik

210 Items

Recent Submissions
Calibration of Polarization Fields and Electro-Optical Response of Group-III Nitride Based c-Plane Quantum-Well Heterostructures by Application of Electro-Modulation Techniques

Papadimitriou, Dimitra N. (2019-12-27)

The polarization fields and electro-optical response of PIN-diodes based on nearly lattice-matched InGaN/GaN and InAlN/GaN double heterostructure quantum wells grown on (0001) sapphire substrates by metalorganic vapor phase epitaxy were experimentally quantified. Dependent on the indium content and the applied voltage, an intense near ultra-violet emission was observed from GaN (with fundamenta...

Generation of maximally entangled states and coherent control in quantum dot microlenses

Bounouar, Samir ; Haye, Christpoh de la ; Strauß, Max ; Schnauber, Peter ; Thoma, Alexander ; Gschrey, Manuel ; Schulze, Jan-Hindrik ; Strittmatter, André ; Rodt, Sven ; Reitzenstein, Stephan (2018-04-12)

The integration of entangled photon emitters in nanophotonic structures designed for the broadband enhancement of photon extraction is a major challenge for quantum information technologies. We study the potential of quantum dot (QD) microlenses as efficient emitters of maximally entangled photons. For this purpose, we perform quantum tomography measurements on InGaAs QDs integrated determinist...

Efficient single-photon source based on a deterministically fabricated single quantum dot - microstructure with backside gold mirror

Fischbach, Sarah ; Kaganskiy, Arsenty ; Tauscher, Esra Burcu Yarar ; Gericke, Fabian ; Thoma, Alexander ; Schmidt, Ronny ; Strittmatter, André ; Heindel, Tobias ; Reitzenstein, Stephan (2017-07-05)

We present an efficient broadband single-photon source which is fabricated by a flip-chip gold-bonding technique and in-situ electron beam lithography. The device comprises a single InGaAs quantum dot that is centered at the bottom of a monolithic mesa structure and located above a gold mirror for enhanced photon-extraction efficiency. We show a photon-extraction efficiency of ηext=(18±2) % int...

Resonance fluorescence of a site-controlled quantum dot realized by the buried-stressor growth technique

Strauß, Max ; Kaganskiy, Arsenty ; Voigt, Robert ; Schnauber, Peter ; Schulze, Jan-Hindrik ; Rodt, Sven ; Strittmatter, André ; Reitzenstein, Stephan (2017-03-12)

Site-controlled growth of semiconductor quantum dots (QDs) represents a major advancement to achieve scalable quantum technology platforms. One immediate benefit is the deterministic integration of quantum emitters into optical microcavities. However, site-controlled growth of QDs is usually achieved at the cost of reduced optical quality. Here, we show that the buried-stressor growth technique...

Enhanced photon-extraction efficiency from InGaAs/GaAs quantum dots in deterministic photonic structures at 1.3 μm fabricated by in-situ electron-beam lithography

Strocka, N. ; Musiał, A. ; Schneider, P.-I. ; Mrowiński, P. ; Holewa, P. ; Burger, S. ; Quandt, D. ; Strittmatter, André ; Rodt, Sven ; Reitzenstein, Stephan ; Sęk, G. (2018-08-07)

The main challenge in the development of non-classical light sources remains their brightness that limits the data transmission and processing rates as well as the realization of practical devices operating in the telecommunication range. To overcome this issue, we propose to utilize universal and flexible in-situ electron-beam lithography and hereby, we demonstrate a successful technology tran...

Micropillars with a controlled number of site-controlled quantum dots

Kaganskiy, Arsenty ; Gericke, Fabian ; Heindel, Tobias ; Porte, Xavier ; Reitzenstein, Stephan (2018-02-12)

We report on the realization of micropillars with site-controlled quantum dots (SCQDs) in the active layer. The SCQDs are grown via the buried stressor approach which allows for the positioned growth and device integration of a controllable number of QDs with high optical quality. This concept is very powerful as the number and the position of SCQDs in the cavity can be simultaneously controlle...

Quantum-optical influences in optoelectronics - an introduction

Chow, Weng W. ; Reitzenstein, Stephan (2018-10-26)

This focused review discusses the increasing importance of quantum optics in the physics and engineering of optoelectronic components. Two influences relating to cavity quantum electrodynamics are presented. One involves the development of low threshold lasers, when the channeling of spontaneous emission into the lasing mode becomes so efficient that the concept of lasing needs revisiting. The ...

Fabrication of dense diameter-tuned quantum dot micropillar arrays for applications in photonic information processing

Heuser, Tobias ; Große, Jan ; Kaganskiy, Arsenty ; Brunner, Daniel ; Reitzenstein, Stephan (2018-09-28)

We report on the realization of a dense, large-scale array of 900 quantum dot micropillar cavities with high spectral homogeneity. We target applications in photonic information processing such as optical reservoir computing which can be implemented in large arrays of optically coupled microlasers. To achieve the required spectral homogeneity for the underlying optical injection locking, we cal...

Anti‐Stokes Photoluminescence of Monolayer WS2

Pierret, Aurélie ; Tornatzky, Hans ; Maultzsch, Janina (2019-10-09)

Anti‐Stokes photoluminescence excitation of a WS2 monolayer flake between 10 and 300 K is reported herein. Even with continuous‐wave lasers at low power, the emission of the exciton at excitation 100 meV below its emission energy at room temperature is observed. A mechanism which involves the trions as the intermediate state is proposed, leading to an efficient up‐conversion process. In additio...

Determination of Sapphire Off‐Cut and Its Influence on the Morphology and Local Defect Distribution in Epitaxially Laterally Overgrown AlN for Optically Pumped UVC Lasers

Enslin, Johannes ; Knauer, Arne ; Mogilatenko, Anna ; Mehnke, Frank ; Martens, Martin ; Kuhn, Christian ; Wernicke, Tim ; Weyers, Markus ; Kneissl, Michael (2019-11-12)

Herein, a systematic study of the morphology and local defect distribution in epitaxially laterally overgrown (ELO) AlN on c‐plane sapphire substrates with different off‐cut angles ranging from 0.08° to 0.23° is presented. Precise measurements of the off‐cut angle α, using a combination of optical alignment and X‐ray diffraction with an accuracy of ±5° for the off‐cut direction and ±0.015° for ...

Optical injection of High-β Quantum Dot Micropillar Lasers

Schlottmann, Elisabeth Anna Katharina (2020)

The huge progress in laser miniaturization opens new fields of research at the crossroads between nanophotonics and nonlinear dynamics. Cavity-enhanced microcavities exhibit lasing close to the quantum regime and are excellent testbeds for exploring nonlinear dynamics at the low-power limit by optical injection. Quantum dot micropillar lasers exhibit a bimodal behavior that features intrinsic d...

Entwicklung und deterministische Herstellung von Mikrolasern und Einzelphotonenquellen auf Basis positionierter Quantenpunkte

Kaganskiy, Arsenty (2020)

Die vorliegende Arbeit beschäftigt sich mit der Entwicklung und Charakterisierung deterministischer Mikrosäulen-Laser und Einzelphotonenquellen auf der Basis von positionierten Halbleiter-Quantenpunkten. Die Positionierung erfolgt über das Konzept vergrabener Stressoren, welches auf einer bevorzugten Nukleation von Quantenpunkten oberhalb einer teilweise oxidierten AlAs-Schicht basiert. Eine wi...

Quantum dot microlasers subject to delayed optical feedback

Holzinger, Steffen Karl (2019)

Semiconductor lasers have been found to be extremely sensitive to back reflections of there own light emission. While corresponding laser reflections are mostly considered a disturbance for many applications, their underlying physics have been an important and attractive research topic in the field of nonlinear dynamics for many years. So far the complex dynamics of feedback-coupled semicondu...

Optical coupling of quantum dot microlasers

Kreinberg, Sören (2019)

Optical coupling in the transition regime between the classical and the quantum regime is an emerging research field. Here, semiconductor quantum dot (QD) micropillar emitters are an ideal test-bed system, as they are situated at the crossroads between nanophotonics and non-linear dynamics. Due to their small mode volume and high resonator Q-factor, they are subject to cavity quantum electro-dy...

Phononic and excitonic properties of transition metal dichalcogenides

Tornatzky, Hans (2019)

Transition metal dichalcogenides (TMDCs) like MoS2, MoSe2, WS2, and WSe2 have attracted enormous interest in the past decade. TMDCs are van-der-Waals crystals with highly anisotropic properties, which allows the exfoliation of individual layers. Their remarkable physical properties, such as the high exciton binding energy and the locking of spin- and valley degree of freedom, make them promisin...

Quantum dots and quantum wires and their usage in future optoelectronic devices in the framework of 8-band kp-theory

Greif, Ludwig Albrecht Thorsten (2019)

Lifelike electronic structure modeling of nanostructures most often leads to multiscale many-particle problems which require the consideration of far- range effects like strain caused by the macroscopic environment as well as the small-scale confinement effect and quantum mechanically phenomena like charge carrier interaction. While already implemented numerical methods like Hartree-Fock (HF) o...

Ultrafast optical demagnetization dynamics in thin elemental films and alloys

Willems, Felix Alexander (2019)

This thesis investigates the femtosecond photo-induced magnetization dynamics in the fundamental transition metals (TMs) Fe, Co, and Ni as well as the technologically relevant, two-component CoPt alloy. In this context, a laboratorybased higher harmonic generation (HHG) source was developed and set up which provides radiation in the extended ultraviolet (XUV) spectral range with pulse lengths o...

Growth and characterization of InN and In-rich InGaN alloys by migration-enhanced plasma-assisted MOCVD

Seidlitz, Daniel (2019)

This thesis investigates and presents the structural and optoelectronic properties of indium nitride (InN) and indium gallium nitride (InGaN) alloys. Furthermore, this work describes the synthesis of group III-nitride alloys using a novel growth technique named migration-enhanced plasma-assisted metalorganic chemical vapor deposition (MEPA-MOCVD). MEPA-MOCVD is an extension of low-pressure MOC...

Prozessierung und Anwendung SiO2 basierter Lichtleiter für die optische UVC-Gassensorik

Elmlinger, Philipp Simon (2019)

Diese Arbeit behandelt die Prozessierung verlustarmer Lichtwellenleiter für einen optischen UVC-Gassensor. Durch optische Simulationen wurde zunächst ein geeignetes Material (amorphes Quarzglas) und Design abgeleitet. Mittels Belichtung mit einem Ultrakurzpulslaser und anschließendem selektiven Nassätzen wurden die Lichtleiter aus dem Wafer strukturiert. Die resultierenden rauen Seitenwände füh...

A Miniaturized UV-LED Based Optical Gas Sensor Utilizing Silica Waveguides for the Measurement of Nitrogen Dioxide and Sulphur Dioxide

Elmlinger, Philipp ; Schreivogel, Martin ; Weida, Simon ; Kneissl, Michael (2017-08-15)

Continuing advances in the development of light-emitting diodes (LEDs) in the deep ultraviolet spectral range (DUV) enable miniaturized, mobile, and cost-effective DUV gas sensors. Efficient light coupling, guiding, and splitting plays a key role for stable sensor systems and is realized by lowloss silica based waveguides, fabricated by ultrashort pulsed laser etching and laser polishing. The t...