Tandem solar cells consist of two individual solar cells, stacked on top of each other. Using two absorbers with different band gap energies, they permit to reduce both, transmission and thermalization losses. Recently, especially silicon/perovskite tandem solar cells are widely investigated in the research community with power conversion efficienc...
Light-emitting diodes (LEDs) are an attractive alternative to lasers for the use as transmitters in optical short-range communications. They are cost-effective and robust against environmental conditions such as varying ambient temperatures. However, in order to be able to maximize the data rate of an LED-based transmission system, detailed knowled...
In the present work, reliability relevant aspects of the processing of (InAlGa)N-based laser diodes with an emission wavelength of 400 nm were investigated. The aim was to increase the lifetime of the laser diodes in continuous wave operation with a high chip yield per wafer. For this purpose, individual steps of the chip processing which limit yie...
This thesis presents the results of the simulation of two different parts from the typical atmospheric interface found in a mass spectrometer: the transfer capillary and the ion funnel. These are usually found in combination with electrospray ionization and allow the transition between atmospheric pressure and vacuum. The main goal of the study is ...
This work investigates several different characterization procedures for parasitic effects in integrated semiconductor devices. It specifically focuses on back-bias induced parasitic effects, such as the forward biased parasitic diode and the parasitic bipolar junction transistor as well as drain-induced barrier lowering and parasitic sub-threshold...
Locations with high direct normal irradiance (DNI) hold significant potential for not only sustainable but also dispatchable electricity generation using concentrated solar power (CSP) technology. Missing financial and regulatory frameworks, weak economies alongside the abundance of cheap fossil fuels in countries with high DNI lead to low developm...
The ability to make predictions about the flow in the wake of a lift-generating body has a range of important applications. One example is the wake of an aircraft, where this flow significantly affects the proximity with which a trailing aircraft can take off, cruise or land. Another application is the placement and operation of wind turbines in a ...
The use of supercritical carbon dioxide (sCO2) cycles in waste heat to power (WHP) applications, specifically in combined-cycle power systems, can help industrial and power generation facilities save money and increase efficiency. According to the literature, the main hindrance facing the commercialization of these systems is their relative novelty...
Due to increasing requirements regarding low energy consumption, the aerodynamic drag of rail vehicles has become more and more important in recent years. Many studies have dealt with the aerodynamic drag in the last decades and have provided a good understanding of fundamentals and boundary conditions. A variety of experimental methods and measure...
Recently, the radioactive PET tracer[18F]NaF previously used in skeletal imaging found acardiac application: it shows uptake in vulnerable high-risk atherosclerotic plaques likely torupture and cause myocardial infarction. Subsequent studies revealed that coronary [18F]NaFuptake provides a powerful predictor of myocardial infarction fatality in pat...
