Practical trainings, student assistants and theses

Transparent conductive oxides (TCOs) are essential components for many everyday applications and devices, such as displays, smart windows, area lighting, flexible electronics, and solar modules. The most commonly used TCO is tin-doped indium oxide (ITO). In order to reduce the demand for the critical raw material indium, zinc oxide-based TCOs often represent a good alternative. However, ZnO is not suitable for applications involving high temperatures or aggressive environments. Tin oxide, SnO2, which exhibits the best thermal and chemical stability among known TCOs, offers a better alternative for applications in concentrated solar power, perovskite solar cells, and as electrodes in high-power electronics.
The most important functional properties of TCOs are high transparency in the visible wavelength range and high electrical conductivity. Both are strongly dependent on point and structural defects in the materials. Interestingly, these defects in SnO₂ are still not sufficiently characterized and understood, and are therefore the subject of ongoing scientific research. To improve the knowledge base of tin oxide-based TCOs, Bachelor's, Master's, or Diploma thesis topics are - among others - offered on the following sub-aspects:
1.) Identification of point defects of undoped Sn oxide thin films and correlation with the electrical properties
2.) Optimization of the electrical and optical properties of doped Sn oxide thin films
3.) Correlation of growth conditions and structural properties of tin oxide thin films
State-of-the-art in-situ and ex-situ methods such as magnetron sputtering, ellipsometry, UV-vis-NIR-FTIR and Raman spectroscopy, and X-ray diffraction will be employed.

• University enrollment in physics, chemistry, or materials science and good grades or better
• Interest, enthusiasm and ability for scientific work
• Basic programming skills and proficiency in using office and scientific software
• Fluent English language skills

• Payment includes the standard expense allowance

1D- und 2D-Ramanspektroskopische Meßreihen oder auch Maps liefern detaillierte ortsaufgelöste chemische Informationen über die untersuchten Proben. Damit kann z. B. die Komponentenverteilung in Stoffgemischen quantitativ bestimmt oder die Homogenität einphasiger Proben gezeigt werden. Andererseits lassen sich lokale Strukturveränderungen, Spannungszustände, Stapelfolgenänderungen in 2D-Materialien und Punktdefekte charakterisieren. Voraussetzung dabei ist eine möglichst engmaschige Datenerfassung bis hin zur Auflösungsgrenze der verwendeten Laserstrahlung sowie eine große Anzahl an Messpunkten. Mit modernen Spektrometern sind Messzeiten im Sekundenbereich gut realisierbar. Die Umsetzung der spektroskopischen in eine chemische Information erfordert dann die Extraktion von Parametern wie Schwingungsfrequenz, Intensität und Linienbreite durch Spektrenanpassung. Die Gerätesoftware bietet dafür nur eingeschränkte Möglichkeiten.
Im Rahmen einer Graduierungsarbeit soll in Zusammenarbeit mit dem HZDR-Rechenzentrum ein Auswertealgorithmus für die automatisierte Auswertung von 1D- und 2D-Ramanspektroskopischen Meßreihen entwickelt, an Beispielen getestet und dokumentiert werden.

1. Studium der Werkstoffwissenschaften, Physik oder Chemie
2. Interesse, Freude und Befähigung für wissenschaftliche Arbeit
3. Grundkenntnisse in Programmierung und sicherer Umgang mit Büro- und wissenschaftlicher Software
4. Sehr gute Englisch-Kenntnisse

Die Arbeit ist in die umfangreichen Aktivitäten der Abteilung Nanoelektronik (FWIO) zu 2D-Werkstoffen eingebettet. Sie kann jederzeit aufgenommen werden.

Tower power plants represent the latest generation of solar thermal power generation systems (see figure). Large-area mirror arrays concentrate sunlight onto a central absorber, where it is converted into thermal energy, which is then transferred to a heat transfer medium. Compared to photovoltaics, solar thermal energy has the inherent advantage of energy storage capacity and availability on demand. The challenge for further increasing the efficiency of solar power plants lies in developing materials with temperature stability up to 800 °C in air. Within the framework of graduate theses and research projects, thermally stable coatings for the core components of solar tower power plants will be developed and tested. State-of-the-art in-situ and ex-situ methods such as magnetron sputtering, ellipsometry, UV-vis-NIR-FTIR retroreflector, and Raman spectroscopy will be employed.
The following tasks are offered in this area:
i) Design and optical simulation of solar-selective coating stacks for solar power plants
ii) Deposition, optimization, and characterization of the structural, optical and electrical properties of individual components and whole coating stacks for solar power plants
iii) Ex situ and in situ investigations of the thermal stability of individual components and entire coating stacks for solar power plants
Other topics can be discussed individually.

1. University program in physics, chemistry, or materials science with good grades or better
2. Interest, enthusiasm, and ability for scientific work
3. Basic programming skills and proficiency in using office and scientific software
4. Fluent English language skills

This work is carried out in collaboration with national and international partners, payment includes the standard expense allowance