Post-Doctoral position-Strain driven Group IV photonic devices: light emission and detection

The CEA IRIG (Institut de Recherche Interdisciplinaire de Grenoble) is located at Grenoble and belongs to the CEA DRF (Fundamental Research Division). The SINAPS laboratory at PHELIQS investigates the new physical phenomena appearing when group IV semiconductors are down-sized to the nanometer scale. SiNaPS research ranges from material growth and nanofabrication to physical study of nanostructures (structural, electronic and optical properties).

Straining the crystal lattice of a semiconductor is a very powerful tool enabling controlling many properties such as its emission wavelength, its mobility. … A forefront challenge is generating strains in the % range, in a controllable and reversible way, which deeply drives the electronic properties of the starting semiconductor. Making strain amplification in microstructures is a rather recent technique allowing accumulating very significant amounts of strain in a micronic constriction, such as a microbridge (up to 4.9% for Ge [1]). So far, the architectures of GeSn microlasers under strong deformation recently demonstrated at the SiNaPS laboratory in the IRIG institute [2], despite a strain induced 50% shrink of the GeSn band gap, cannot afford modulating on demand the applied strain within the very same device, the latter being frozen “by design”. The target of this 18 months post doc is to fabricate photonic devices of the MOEMS family (Micro-Opto-ElectroMechanical Systems) allowing combining the local strain amplification in the semiconductor and actuation features of strain through an external stimulus, with the objectives to move towards: 1-a wide band tunable laser microsource via external command and 2-new types of photodetectors, both in a Group IV technology (Si, Ge and Ge_1-xSn_x). This work is part of a broader collaboration between the IRIG and LETI institutes concerning the study of Si compatible Group IV laser sources and will be based at the SiNaPS laboratory of the IRIG institute. A strong interaction with the LETI partners is expected (collaboration around the growth and material aspects).

[1] A. Gassenq et al, Appl. Phys. Lett.108, 241902 (2016)

[2] J. Chrétien et al, ACS Photonics2019, 6, 10, 2462–2469.

The candidate will fabricate the devices at the Plateforme Technologique Amont (PTA: lithography, dry etching, metallization, bonding) and carry out the optics and material characterizations (microRaman, photoluminescence, SEM) at IRIG and LETI. The candidate must hold a PhD in the field of semiconductors physics or photonics (knowledge in device operation, semiconductor physics and photonics, and optical characterization of semiconductors), as well as skills in micro-nanofabrication.

This project also requires good communication skills (reports, meetings, scientific communications).