Inst. Hochfrequenz- und Halbleiter-Systemtechnologien

152 Items

Recent Submissions
Concept development and implementation of online monitoring methods in the transfer molding process for electronic packages

Kaya, Burcu (2018)

The transfer molding process is one of the major processes for the encapsulation of electronic packages. To provide a structural support and to protect the electronic components from the environment, epoxy molding compounds (EMCs) are mainly used as encapsulation material. The quality of the molded packages depends strongly on the process parameters of the transfer molding process and also the ...

Tailor-made light management textures for liquid phase crystallized silicon solar cells

Eisenhauer, David (2018)

The aim of this thesis is the identification and implementation of tailored light management textures for liquid phase crystallized silicon thin-film solar cells on glass. To do this, textures that combine excellent anti-reflective properties in the wavelength range of interest and a consistent silicon material quality compared to reference cells need to be established. Two approaches for light...

Interdigitated back contact silicon heterojunction solar cells

Stang, Johann-Christoph (2018)

This work follows two routes: the first one explores the efficiency potential of IBC SHJ solar cells built with a rather complex process, the second one shows ways to make this efficiency potential actually industrially accessible by developing an appropriate, simplified manufacturing process. In chapter 4, both manufacturing processes are discussed. In the first part, the established photolit...

Wideband GaN microwave power amplifiers with class-G supply modulation

Wolff, Nikolai (2018)

The continuous and rapidly growing demand for mobile communication access led worldwide to a major increase in the number of base stations to provide the sufficient coverage and quality of service. As a consequence, mobile communication networks have become a significant contributor to the worldwide energy consumption. The necessity to save operational cost and the increased energy awareness fu...

Modeling and characterization of PCB coils for inductive wireless charging

Curran, Brian ; Maaß, Uwe ; Fotheringham, Gerhard ; Stevens, Nobby ; Ndip, Ivan ; Lang, Klaus-Dieter (2015)

Wireless charging is emerging as a viable technology in many industries, including consumer, medical, and sensor electronics. An investigation of design principles is conducted for a wireless charging platform that is designed to charge devices of different sizes and technologies, using only through vias. It is shown that at a 5 mm separation distance, a coupling coefficient can be achieved whi...

Adhesion mechanism between laser sputtered materials, Copper and Aluminum on Silicon substrate

Azhdast, Mohammad Hossein (2018)

The present study aims to the novel technique by laser deposition of Aluminum and Copper nano particles on silicon wafer substrate. Thin µm films have been deposited from one-side coated glass to Silicon wafers by sputtering nano particles using laser radiation. The Distance between donor film and substrate was up to several 100 µm, and it has been optimized as 300 µm. As soon as the laser en...

Entwicklung einer Hybridsolarzelle mit CuInSe2 und den kleinen organischen Molekülen ZnPc und C60

Morzé, Natascha von (2018)

Bei der vorliegenden Arbeit handelt es sich um eine Machbarkeitsstudie einer Hybridsolarzelle mit dem anorganischen Absorber CuInSe2 und den kleinen organischen Molekülen ZnPc und C60. Ähnlich wie bei einer Tandemsolarzelle soll bei diesem Konzept der Absorber CuInSe2 die Sonnenenergie im Infrarotbereich in Strom umwandeln und das Farbstoffmolekül ZnPc im sichtbaren Bereich. Das Fulleren C60 di...

Tentative designs for X- and W-band klystrons with corkscrew-modulated hollow electron beam

Nie, Jiwei (2018)

Klystrons employing a hollow beam provides much higher RF power, compared to solid state amplifiers and compared to klystrons employing a pencil beam. This is the most important reason for the development of klystrons employing a hollow beam. This paper presents tentative designs for X-band and W-band klystrons with corkscrew-modulated hollow electron beam. The X-band TM110-mode klystron opera...

Distortion in microwave class-S power amplifiers

AL-Mozani, Dhamia (2018)

To tackle the critical challenge in microwave transmitters of achieving high efficiency at higher power back-offs, class-S power amplifier, as promising class of operation, attracts the attention since some time ago. It provides a theoretical efficiency of 100% regardless of power back-off which is required nowadays in wireless communication infrastructure. The current work focused on the class...

Investigation of hybrid organic-inorganic lead halide perovskites by modulated surface photovoltage spectroscopy

Omondi, Celline Awino (2018)

Hybrid organic-inorganic metal halide perovskites (called here perovskites) have emerged as a new group of materials for highly efficient solar cells (SCs) based on earth abundant elements which can be processed from solutions at low temperature. CH3NH3Pb(I1-xBrx)3 perovskite films were studied in the thesis since it belongs to the materials which are of great interest for top SCs in tandem SCs...

Back- and front-side texturing for light-management in perovskite / silicon-heterojunction tandem solar cells

Jošt, Matej ; Albrecht, Steve ; Lipovšek, Benjamin ; Krč, Janez ; Korte, Lars ; Rech, Bernd ; Topič, Marko (2016-12)

The perovskite / silicon-heterojunction (SHJ) tandem solar cell can theoretically overcome the efficiencies of the single junction solar cells with experimental results not far behind. Here, we use optical simulations to analyze the potential of such currently feasible monolithic perovskite / SHJ tandem devices. We consider three different device designs in the optical simulations: planar devic...

Design of high performance indium phosphide (InP) - based quantum dot light emitting diodes (QLEDs)

Kim, Yohan (2018)

This dissertation is dedicated to the development and understanding of fundamental device mechanism and engineering of the device architecture of quantum dot light-emitting diodes (QLEDs) based on indium phosphide (InP) quantum dots. QLEDs have emerged as a next-generation flat panel display (FPD) technology with promising properties. Their device performance and fabrication methods are develop...

Optical interactions for internal signal tracking in ICs

Vogt, Ivo (2018)

This work investigates and improves two common techniques of electronics failure analysis, (spectral) photon emission microscopy (PEM/SPEM) and electro-optical frequency mapping (EOFM). The scientific focus is set on the physical interaction between light and an active semiconductor device. Investigated test structures include 14-40nm FinFETs of several technology generations, as well as planar...

Polycrystalline silicon solar cells on glass - toward an industry compatible process

Frijnts, Tim Robin (2018)

Multicrystalline silicon wafer based solar cells are currently the dominating photovoltaic technology. Liquid phase crystallized, thin film, polycrystalline silicon on glass (LPC-Si) is a promising approach to reduce the cost of crystalline silicon solar cells. In this thesis the large area plasma enhanced chemical vapour deposition (PECVD) of SiOx/SiNx/SiOxNy interlayers and 5-15 µm amorphous...

Device simulation of high-performance SiGe heterojunction bipolar transistors

Korn, Julian (2018)

Silicon-germanium (SiGe) heterojunction bipolar transistors (HBT) are well suited for high-frequency applications. Their performance has been improved continuously in recent years. Today's SiGe HBT technologies show transit frequencies fT up to 300 GHz and maximum oscillation frequencies up to 500 GHz. Numerical device simulation plays an important role in the development of SiGe HBTs. Possible...

Analysis of photonic crystals for interaction with near-surface emitters

Barth, Carlo (2018)

The tailorable optical properties of photonic crystals enable a broad spectrum of applications beyond just the photonic bandgap. Leaky modes of photonic crystal slabs which couple to the external light field can facilitate light extraction from emitters located inside the slab or near the surface, known as the enhanced extraction effect. This effect can enhance light-emitting diodes or the outp...

Insights into the reversibility of aluminum graphite batteries

Elia, Giuseppe Antonio ; Hasa, Ivana ; Greco, Giorgia ; Diemant, Thomas ; Marquardt, Krystan ; Hoeppner, Katrin ; Behm, R. Jürgen ; Hoell, Armin ; Passerini, Stefano ; Hahn, Robert (2017)

Herein we report a novel study on the reaction mechanism of non-aqueous aluminum/graphite cell chemistry employing 1-ethyl-3-methylimidazolium chloride:aluminum trichloride (EMIMCl:AlCl3) as the electrolyte. This work highlights new insights into the reversibility of the anion intercalation chemistry besides confirming its outstanding cycle life exceeding 2000 cycles, corresponding to more than...

The Influence of ITO Dopant Density on J-V Characteristics of Silicon Heterojunction Solar Cells: Experiments and Simulations

Kirner, Simon ; Hartig, Manuel ; Mazzarella, Luana ; Korte, Lars ; Frijnts, Tim ; Scherg-Kurmes, Harald ; Ring, Sven ; Stannowski, Bernd ; Rech, Bernd ; Schlatmann, Rutger (2015)

The TCO/a-Si:H(p) contact is a critical part of the silicon heterojunction solar cell. At this point, holes from the emitter have to recombine loss free with electrons from the TCO. Since tunneling is believed to be the dominant transport mechanism, a high dopant density in both adjacent layers is critical. In contrast to this, it has been reported that high TCO dopant density can reduce field ...

Front-side interface engineering for liquid-phase crystallized silicon solar cells on glass

Preissler, Natalie (2018)

Liquid-phase crystallization (LPC) is a process technology to fabricate thin (< 30 μm) crystalline silicon layers on glass substrates. To this end, as-deposited amorphous or nano-crystalline silicon layers on glass are molten locally with a high energy density source (laser or electron beam). Subsequently, the silicon cools down and crystallizes. Resulting layers exhibit grains with a length of...

24 GHz low-power switch-channel CMOS transceiver for wireless localization

Zhang, Tao ; Hamidian, Amin ; Shu, Ran ; Subramanian, Viswanathan (2014)

A 24 GHz low-power transceiver is designed, fabricated, and characterized using 130 nm complementary metal-oxide semiconductor (CMOS) process. The designed transceiver is targeted for frequency-modulated-continuous-wave (FMCW) wireless local positioning. The transceiver includes four switchable receiving channels, one transmitting channel and local-oscillator generation circuitries. Several pow...