(Si)GeSn Semiconductors for integrated optoelectronics and quantum electronics

(Si)GeSn Semiconductors for integrated optoelectronics and quantum electronics

Simone Assali

Ecole Polytechnique de Montreal, Canada

Nanoscale heterostructures and low-dimensional systems enable a precise and simultaneous control of lattice parameter and band gap in conventional III-V semiconductors. Extending this paradigm to group-IV semiconductors will pave the way in creating an entirely new class of scalable photonic, optoelectronic, and quantum devices on a Silicon substrate. Major improvements in the fabrication of a fully-group IV integrated photonic platform were recently achieved with the development of Germanium-Tin (GeSn) alloys.[1] In this material system, efficient light absorption and emission at infrared wavelengths (above 2.0 μm) is obtained when increasing the Sn incorporation above 10 at.%. The ability to incorporate Sn atoms in Ge at concentrations about one order of magnitude higher than the 1 at.% equilibrium solubility is at the core of these emerging technologies.

In this presentation, the recent progress in the epitaxial growth and optoelectronic properties of GeSn low-dimensional systems will be discussed from the macroscopic level down to the atomic scale in nanowires[2-3] and thin film[4-5] heterostructures. The relevance of these semiconductors for the development of room-temperature optical communication, sensing, and imaging technologies operating at infrared wavelengths will be discussed form both materials and device perspectives. Moreover, the possibility to implement novel scalable quantum devices using group-IV semiconductors will be addressed, paving the way to manipulate spin along with coherent optical transition in spin qubits.[6]


[1] O. Moutanabbir et al., Monolithic Infrared Silicon Photonics: The Rise of (Si)GeSn Semiconductors, Appl. Phys. Lett., 118, 110502 (2021).

[2] S. Assali et al., Growth and Optical Properties of Direct Band Gap Ge/Ge0.87Sn0.13 Core/Shell Nanowire Arrays, Nano Letters 17 (3), 1538–1544 (2017).

[3] L. Luo et al., Highly Responsive Extended-SWIR Photodetection in All-Group IV Core/Shell Nanowires, ACS Photonics 9 (3), 914-921 (2022).

[4] S. Assali et al., Atomically uniform Sn-rich GeSn semiconductors with 3.0-3.5 μm room-temperature optical emission, Appl. Phys. Lett. 112, 251903 (2018).

[5] M.R.M. Atalla et al., High-Bandwidth Extended-SWIR GeSn Photodetectors on Silicon Achieving Ultrafast Broadband Spectroscopic Response, ACS Photonics, 9 (4), 1425–1433 (2022).

[6] S. Assali et al., A Light-Hole Germanium Quantum Well on Silicon, arXiv:2112.15185.

Host: J. M. Pitarke


nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian


Simone Assali, Ecole Polytechnique de Montreal, Canada

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