Alloyed materials for photonics: exploring dielectric response in group IV nanowires

Term and Location A 18-month post-doctoral position is available in the STEM group at the Laboratoire de Physique des Solides of Université Paris-Saclay (Orsay, France) beginning as early as February 2024. The position is funded in the context of the French ANR project AMPHORE.

Scientific context Over the last few years, the emergence of data-intensive technological areas has triggered an urgent need for implementing telecommunication functionalities in group IV materials. This has encouraged researchers to develop novel direct bandgap systems while keeping their compatibility with Si CMOS electronics. These systems would make it possible to unite electronic and optoelectronic features on a single chip. Such an achievement would pave the way to a new Si technological revolution without the need for the challenging III-V heterogeneous integration. Among the variety of materials investigated, hexagonal-diamond Si1-xGex alloyed nanowires (2H-Si1-xGex NWs) are extremely attractive due to their easiness of fabrication and peculiar optical features. Indeed, although 2H-Si bulk is stable only at very high pressures, recent studies demonstrated that at the nanoscale, 2H-SiGe crystals can exist as pure wires. These nanostructures offer the unique possibility to combine an indirect semiconductor (2H-Si) with a direct one (2H-Ge) to obtain a light-emitting direct bandgap material in the telecommunication wavelength range.

Project description The successful candidate will investigate, through the effectual combination of ab initio approaches, semi-empirical methods, and computer simulations, the potentialities of 2H-Si1-xGex NWs as light emitters. The main goal is to reach a deep theoretical understanding, via precise state-of-the-art quantum-mechanical modeling, of the dielectric response of 2H-Si1-xGex NWs in a realistic environment, including morphology, substrates, and dopants. Furthermore, the activity will provide an accurate interpretation of targeted experiments using advanced nanometre-scale optical measurements with fast electrons that will be conducted in the group.

Profile candidate Candidates with previous experience in computational materials science, a track record of peer-reviewed publications, the ability to work independently, and excellent organization and communication skills are strongly encouraged to apply. Applicants with expertise in DFT-based methods and nanostructures are preferred. Programming experience is also desirable, but not mandatory. We are seeking creative and highly motivated individuals well trained and skilled in scientific research, and willing to collaborate in an interdisciplinary team in connection with experimentalists. Presentations at national/international meetings and publication of scientific results in high-profile peer-reviewed journals are expected.

How to apply For information on the research group please visit the website https://equipes2.lps.u-psud.fr/stem/. Qualified candidates should send a CV, a list of publications, contact details of at least two references, and an estimated availability date to Michele Amato ([email protected]). The preferred format is a single PDF document.

Closing Date Candidatures will be considered right up until the position is filled.