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A new class of optoelectronic devices, such as single-photon sources, is based on semiconductor quantum dots (QDs) embedded in a photonic structure. Nowadays, the best QDs are still obtained
via a self-assembly process: these emitters are thus randomly located in the structure.
Pinpointing the exact positions of the dots in the material is a challenging task, which could greatly help the characterization and engineering of these devices. In this context, researchers at our laboratory and at Néel Institute developed an original position mapping technique. By generating a controlled and inhomogeneous strain in the photonic structure, one induces a spectral shift of the QD emission, whose magnitude and sign depend on the local strain. Monitoring the QD emission change by optical spectroscopy thus yields the QD position with an accuracy that can be as low as 1 nanometer. This technique was demonstrated on a photonic wire embedding a single sheet of self-assembled QDs (Figure). Material strain was here obtained by the selective excitation of mechanical vibration modes. Combining the results obtained from the excitation of two orthogonal flexural modes, one obtains a map of the QD position in the growth plane. In the future, this approach could be applied to locate QDs embedded in other photonic structures
micropillar) and could be extended to other quantum emitters which are sensitive to strain.
Thesis presented March 05, 2024 by Matteo Finazzer.
Thesis presented December 20, 2023 by Sylvain Perret.
Thesis presented December 18, 2023 by Maxime Gaignard.
Thesis presented December 05, 2022 by Raouia Rhazi. PhD thesis available as a pdf file.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.