University of Basel

Current research projects

Phonon interference and coherent phonon transport


phonontransport Photons and electrons have been subject of studies exploiting their quantum-mechanical nature for a long time. We aim at exploring the quantum-mechanical nature of collective excitations like phonons, which is crucial for the understanding of the physics and the development of sonic and thermal materials and devices.
Specifically, the wave-particle crossover for phonons will be explored by performing spatially- and time-resolved Inelastic Light Scattering experiments on tailored nanostructures such as nanowires.


Thermoelectric properties of nanowires


thermoelectric device Waste heat recovery through high-efficiency thermoelectric converters can have a major impact on energy production and enable new self-powered device applications. However, the adoption of thermoelectric devices is nowadays limited by their poor efficiency: good thermoelectric materials should exhibit high power factor and low thermal conductivity, an elusive target that has challenged researchers for decades.

One of the most common ways to increase the figure of merit of a material is to decouple its thermal and electrical conductivities. By designing nanostructures with length scales smaller than the phonon mean free path but larger than the electron mean free path, phonon scattering will be enhanced while keeping carrier mobility almost unaffected. For this reason, filamentary crystals such as nanowires are ideal thermoelectric materials. In our group, the thermoelectric properties of individual nanowires will be extensively investigated with the use of suspended SiNx membranes with integrated microheaters, which allows to determine all the parameters entering into the figure of merit of a thermoelectric device.