Felix Basse

Synthesis and thermoelectric properties of RuO2 nanorods

We have explored the effect of the O/Ru ratio on the morphology and the Seebeck coefficient of RuO2 nanorods (space group P42/mnm) synthesized by reactive sputtering. At an O/Ru ratio of 1.69, a faceted surface is observed, while nanorod formation occurs at O/Ru ratios of 2.03 and 2.24. Using classical molecular dynamics with the potential parameters derived in this work, we show that volatile species enable nanorod formation. Based on ab initio calculations, two effects of the nanorod formation on the Seebeck coefficient are observed: (i) increase due to additional states in the vicinity of the Fermi level and (ii) decrease due to oxygen point defects (volatile species). These two competing effects give rise to a moderate increase in the Seebeck coefficient upon nanorod formation.

Multifold Seebeck increase in RuO2 films by quantum-guided lanthanide dilute alloying

Ab initio predictions indicating that alloying RuO2 with La, Eu, or Lu can increase the Seebeck coefficient α manifold due to quantum confinement effects are validated in sputter-deposited La-alloyed RuO2 films showing fourfold α increase. Combinatorial screening reveals that α enhancement correlates with La-induced lattice distortion, which also decreases the thermal conductivity twentyfold, conducive for high thermoelectric figures of merit. These insights should facilitate the rational design of high efficiency oxide-based thermoelectrics through quantum-guided alloying.

Analysis of the potential benefits of digital assembly instructions for single and small batch production

This paper presents the results of a study that was conducted in the Demonstration Factory Aachen in order to analyze the potential benefits of digital assembly instructions compared to paper-based ones. The aim of this study is to validate three hypotheses regarding the benefits in terms of productivity, quality and learning rate. The results will be used to assess the benefits of a potential rollout of digital assembly instructions in a German mid-size company that assembles multi-variant products in the machining equipment sector.