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Proposal for a post-doctoral fellowship

Strain driven Group IV photonic devices: Applications to light emission and detection

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Published on 6 September 2022
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 IRIG/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 nanostructure structural, electronic and optical properties.

Summary of the project
Straining the crystal lattice of a semiconductor is a very powerful tool enabling controlling many properties such as its emission wavelength, its mobility…Modulating and controlling the strain in a reversible fashion and in the multi% range is a forefront challenge. 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]), which deeply drives the electronic properties of the starting semiconductor. Nevertheless, the architectures of GeSn microlasers under strong deformation and recently demonstrated at the SiNaPS laboratory in the IRIG institute [2] cannot afford modulating on demand the applied strain and thus the emission wavelength 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 via an external stimulus, with the objectives to go towards: 1-a wide band wavelength tunable laser microsource via external command and 2-new types of photodetectors, both in a Group IV technology (Si, Ge and Ge1-xSnx). 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). The candidate will have to fabricate the devices in clean room at the Plateforme Technologique Amont (PTA: lithography, dry etching, metallization, bonding) and to carry out the optics and material characterizations (photoluminescence, microRaman, SEM…). A PhD in the field of semiconductors physics or photonics, as well as strong skills in micro-nanofabrication are required.

Example of a Si compatible (GeSn) microlaser with strained gain medium for tuning of the laser emission wavelength.

Desired start date
January 02, 2023

Nicolas Pauc 

Place of work
PHELIQS Laboratory

[1] A. Gassenq et al, Accurate strain measurements in highly strained Ge microbridges, Appl. Phys. Lett. 108: 241902 (2016)
[2] J. Chrétien et al, GeSn lasers covering a wide wavelength range thanks to uniaxial tensile strain, ACS Photonics6(10): 2462–2469 (2019)