Inst. Hochfrequenz- und Halbleiter-Systemtechnologien

208 Items

Recent Submissions
PLATE – Product lifetimes and the environment

(2021)

The current systems of consumption and production cause long-lasting social-ecological damage and a fundamental change seems inevitable, if livelihoods of present and future generations are to be preserved. The lifetimes of products and their performance concerning reliability, functionality, re-usability and recyclability are core issues in the transformation from a linear to a more sustainabl...

Transparent conductive oxides for silicon heterojunction solar cells: interaction between materials and device

Cruz Bournazou, Alexandros (2021)

Crystalline-silicon (c-Si) based solar cells are the dominating technology supplying the market of photovoltaic modules presently and a sustainable method of electricity generation. One promising solar cell concept that can boost the efficiency of this technology and is gaining on industrial relevance is the silicon heterojunction (SHJ) solar cell. In this work, the behavior of three industri...

Minimising optical and electrical losses in perovskite solar cells

Tockhorn, Philipp (2021)

Hybrid organic-inorganic perovskites are considered a promising material class for the application in single- and multi-junction solar cells. Prior to the commercialisation of such solar cells, further understanding of the device physics has to be gained. This dissertation addresses the optimisation of perovskite solar cell (PSC) single-junction devices for the application in perovskite/silicon...

Plasma Assisted Reduction of Graphene Oxide Films

Vinoth Kumar, Sri Hari Bharath ; Muydinov, Ruslan ; Szyszka, Bernd (2021-02-03)

The past decade has seen enormous efforts in the investigation and development of reduced graphene oxide (GO) and its applications. Reduced graphene oxide (rGO) derived from GO is known to have relatively inferior electronic characteristics when compared to pristine graphene. Yet, it has its significance attributed to high-yield production from inexpensive graphite, ease of fabrication with sol...

Comparison of Chloroaluminate Melts for Aluminum Graphite Dual‐Ion Battery Application

Elia, Giuseppe Antonio ; Hoeppner, Katrin ; Hahn, Robert (2020-11-23)

Herein, we report a comparison of aluminum graphite dual‐ion cells (AGDICs) electrochemical characteristics employing the conventional 1‐ethyl‐3‐methylimidazolium chloride:aluminum trichloride (EMIMCl : AlCl3) electrolyte and two popular deep eutectic solvents (DESs), namely urea : AlCl3 and acetamide:AlCl3. The three electrolytes′ characteristics have been evaluated in terms of Al‐stripping de...

Laser patterning of chalcopyrite and perovskite based solar cells: investigation of the laser-material interaction and laser-induced damages

Schultz, Christof (2021)

In this thesis the laser-material interaction processes for the creation of a monolithic interconnection for CIGSe and perovskite solar cells were investigated. By revealing these processes and their influence on the electrical, compositional, and structural properties of the solar cell materials in the vicinity of the laser scribed lines, material-specific ablation models were derived. Thereby...

Interdigitated back-contact silicon heterojunction solar cells: development of patterning techniques and applications in tandem devices

Wagner, Philipp (2021)

In this thesis, interdigitated back-contacted silicon heterojunction (IBC SHJ) solar cells have been investigated. This technology enables record power conversion efficiencies (PCEs) of 26.7%, but suffers from increased fabrication complexity as photolithography is not feasible in the cost-driven photovoltaics (PV) industry. Two patterning techniques for fabricating IBC SHJ solar cells have bee...

Integrated low-power millimeter-wave sensor circuits for biomedical applications

Jamal, Farabi Ibne (2021)

This work presents the design, implementation and demonstration of high-frequency integrated self-sustained dielectric sensor circuits for biomedical applications.Resonance sensing technique has been introduced in this work by using planar microstrip open- and shunt-stubs as the sensing elements at K-band frequencies. The sensing stubs have been employed in Colpitts oscillators as resonators an...

Simultaneous X‐Ray Diffraction and Tomography Operando Investigation of Aluminum/Graphite Batteries

Elia, Giuseppe Antonio ; Greco, Giorgia ; Kamm, Paul Hans ; García‐Moreno, Francisco ; Raoux, Simone ; Hahn, Robert (2020-09-06)

Rechargeable graphite dual‐ion batteries are extremely appealing for grid‐level stationary storage of electricity, thanks to the low‐cost and high‐performance metrics, such as high‐power density, energy efficiency, long cycling life, and good energy density. An in‐depth understanding of the anion intercalation mechanism in graphite is fundamental for the design of highly efficient systems. In t...

Encoding electromagnetic transformation laws for dimensional reduction

Lehmann, Marcus Christian ; Hadžiefendić, Mirsad ; Piwonski, Albert ; Schuhmann, Rolf (2020-05-25)

Electromagnetic phenomena are mathematically described by solutions of boundary value problems. For exploiting symmetries of these boundary value problems in a way that is offered by techniques of dimensional reduction, it needs to be justified that the derivative in symmetry direction is constant or even vanishing. A generalized notion of symmetry can be defined with different directions at ev...

On the Feasibility of Fan-Out Wafer-Level Packaging of Capacitive Micromachined Ultrasound Transducers (CMUT) by Using Inkjet-Printed Redistribution Layers

Roshanghias, Ali ; Dreissigacker, Marc ; Scherf, Christina ; Bretthauer, Christian ; Rauter, Lukas ; Zikulnig, Johanna ; Braun, Tanja ; Becker, Karl-F. ; Rzepka, Sven ; Schneider-Ramelow, Martin (2020-05-31)

Fan-out wafer-level packaging (FOWLP) is an interesting platform for Microelectromechanical systems (MEMS) sensor packaging. Employing FOWLP for MEMS sensor packaging has some unique challenges, while some originate merely from the fabrication of redistribution layers (RDL). For instance, it is crucial to protect the delicate structures and fragile membranes during RDL formation. Thus, additive...

In vivo detection of changes in cutaneous carotenoids after chemotherapy using shifted excitation resonance Raman difference and fluorescence spectroscopy

Jung, Sora ; Darvin, Maxim E. ; Schleusener, Johannes ; Thiede, Gisela ; Lademann, Juergen ; Braune, Marcel ; Maiwald, Martin ; Sumpf, Bernd ; Tränkle, Günther ; Kutzer, Dunja ; Elban, Felia ; Fuss, Harald (2020-01-06)

Background: Various cutaneous toxicities under chemotherapy indicate a local effect of chemotherapy by secretion after systemic application. Here, changes in the fluorescence and Raman spectral properties of the stratum corneum subsequent to intravenous chemotherapy were assessed. Methods: Twenty healthy subjects and 20 cancer patients undergoing chemotherapy were included. Measurement time po...

Autocatalytic Carbonyl Arylation through In Situ Release of Aryl Nucleophiles from N‐Aryl‐N′‐Silyldiazenes

Chauvier, Clément ; Finck, Lucie ; Irran, Elisabeth ; Oestreich, Martin (2020-03-10)

A method for the catalytic generation of functionalized aryl alkali metals is reported. These highly reactive intermediates are liberated from silyl‐protected aryl‐substituted diazenes by the action of Lewis basic alkali metal silanolates, resulting in desilylation and loss of N2. Catalytic quantities of these Lewis bases initiate the transfer of the aryl nucleophile from the diazene to carbony...

How To Quantify the Efficiency Potential of Neat Perovskite Films: Perovskite Semiconductors with an Implied Efficiency Exceeding 28%

Stolterfoht, Martin ; Grischek, Max ; Caprioglio, Pietro ; Wolff, Christian M. ; Gutierrez‐Partida, Emilio ; Peña‐Camargo, Francisco ; Rothhardt, Daniel ; Zhang, Shanshan ; Raoufi, Meysam ; Wolansky, Jakob ; Abdi‐Jalebi, Mojtaba ; Stranks, Samuel D. ; Albrecht, Steve ; Kirchartz, Thomas ; Neher, Dieter (2020-03-12)

Perovskite photovoltaic (PV) cells have demonstrated power conversion efficiencies (PCE) that are close to those of monocrystalline silicon cells; however, in contrast to silicon PV, perovskites are not limited by Auger recombination under 1‐sun illumination. Nevertheless, compared to GaAs and monocrystalline silicon PV, perovskite cells have significantly lower fill factors due to a combinatio...

On the Origin of the Ideality Factor in Perovskite Solar Cells

Caprioglio, Pietro ; Wolff, Christian M. ; Sandberg, Oskar J. ; Armin, Ardalan ; Rech, Bernd ; Albrecht, Steve ; Neher, Dieter ; Stolterfoht, Martin (2020-06-05)

The measurement of the ideality factor (nid) is a popular tool to infer the dominant recombination type in perovskite solar cells (PSC). However, the true meaning of its values is often misinterpreted in complex multilayered devices such as PSC. In this work, the effects of bulk and interface recombination on the nid are investigated experimentally and theoretically. By coupling intensity‐depen...

The Role of Grain Boundaries on Ionic Defect Migration in Metal Halide Perovskites

Phung, Nga ; Al‐Ashouri, Amran ; Meloni, Simone ; Mattoni, Alessandro ; Albrecht, Steve ; Unger, Eva L. ; Merdasa, Aboma ; Abate, Antonio (2020-04-19)

Halide perovskites are emerging as revolutionary materials for optoelectronics. Their ionic nature and the presence of mobile ionic defects within the crystal structure have a dramatic influence on the operation of thin‐film devices such as solar cells, light‐emitting diodes, and transistors. Thin films are often polycrystalline and it is still under debate how grain boundaries affect the migra...

Development of ultra sensitive localisation techniques for failure analysis of soft breakdown events in low K dielectrics

Herfurth, Norbert (2020)

The phenomenon of generating a soft breakdown defect on degrading low k dielectric materials has been observed for many years. So far, the development of such defects has not been fully understood. For the reconstruction of said developments, it is necessary to perform a detailed physical defect analysis. This thesis describes a detailed way to develop failure analysis methods for low k dielec...

A deep ultraviolet laser light source by frequency doubling of GaN based external cavity diode laser radiation

Ruhnke, Norman (2020)

A compact and portable laser light source emitting in the wavelength range between 210 nm and 230 nm would enable numerous applications especially outside the laboratory environment such as sterilization and disinfection of medical equipment, water purification, gas and air analysis by means of absorption spectroscopy, or the identification and quan- tification of proteins and biomolecules by m...

Design and performance analysis of integrated focusing grating couplers for the transverse-magnetic TM00 mode in a photonic BiCMOS technology

Georgieva, Galina ; Voigt, Karsten ; Peczek, Anna ; Mai, Christian ; Zimmermann, Lars (2020-04-08)

Focusing grating couplers for the excitation of the fundamental transverse-magnetic (TM) mode in integrated silicon photonic waveguides are designed and characterized under the boundary conditions of a photonic BiCMOS foundry. Two types of waveguide geometries are considered – a nanowire and a rib waveguide. Wafer-scale experimental results for nanowire TM grating couplers are in excellent agre...

MM-wave RF-MEMS switches in SiGe BiCMOS technologies

Tolunay Wipf, Selin (2020)

In the last decade, silicon germanium (SiGe) bipolar complementary metal oxide semiconductor (BiCMOS) technologies opened a new cost-efficient market for the mm-wave applications. Starting with the commercial use of automotive radars at 77 GHz, the market now has a strong interest on radar, sensor and imaging products at mm-wave and sub-THz frequencies. The latest developments on SiGe hetero bi...