Bright Electrically Controllable Quantum‐Dot‐Molecule Devices Fabricated by In Situ Electron‐Beam Lithography. Issue 6 (3rd May 2021)

• Record Type: Journal Article
• Authors: Schall, Johannes; Deconinck, Marielle; Bart, Nikolai; Florian, Matthias; von Helversen, Martin; Dangel, Christian; Schmidt, Ronny; Bremer, Lucas; Bopp, Frederik; Hüllen, Isabell; Gies, Christopher; Reuter, Dirk; Wieck, Andreas D.; Rodt, Sven; Finley, Jonathan J.; Jahnke, Frank; Ludwig, Arne; Reitzenstein, Stephan
• Is Part Of: Advanced quantum technologies. Volume 4:Issue 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-03
• Subjects: circular Bragg gratings -- determinsitic device fabrication -- quantum dot molecules -- quantum light sources -- quantum memory; Quantum theory -- Periodicals; Quantum computing -- Periodicals; Quantum chemistry -- Periodicals; Quantum electronics -- Periodicals; 537.5
• DOI: 10.1002/qute.202100002
• Languages: English
• ISSNs: 2511-9044

Abstract

Abstract: Self‐organized semiconductor quantum dots represent almost ideal two‐level systems, which have strong potential to applications in photonic quantum technologies. For instance, they can act as emitters in close‐to‐ideal quantum light sources. Coupled quantum dot systems with significantly increased functionality are potentially of even stronger interest since they can be used to host ultra‐stable singlet‐triplet spin qubits for efficient spin‐photon interfaces and for deterministic photonic 2D cluster‐state generation. An advanced quantum dot molecule (QDM) device is realized and excellent optical properties are demonstrated. The device includes electrically controllable QDMs based on stacked quantum dots in a pin‐diode structure. The QDMs are deterministically integrated into a photonic structure with a circular Bragg grating using in situ electron beam lithography. A photon extraction efficiency of up to (24 ± 4)% is measured in good agreement with numerical simulations. The coupling character of the QDMs is clearly demonstrated by bias voltage dependent spectroscopy that also controls the orbital couplings of the QDMs and their charge state in quantitative agreement with theory. The QDM devices show excellent single‐photon emission properties with a multi‐photon suppression of g ( 2 ) ( 0 ) = ( 3.9 ± 0.5 ) × 10 − 3 . These metrics make the developed QDM devices attractive building blocks for use in future photonic quantum networks using advanced nanophotonic hardware. Abstract : Quantum dot molecules (QDMs) can enable efficient spin‐photon interfaces and photonic 2D cluster‐state generation for applications in photonic quantum technologies. The deterministic fabrication of electrically controlled QDM devices with cavity‐enhanced photon extraction efficiency of (24 ± 4)% and g ( 2 ) ( 0 ) = ( 3.9 ± 0.5 ) × 10 − 3 is reported on. These metrics make the QDM devices attractive building blocks for use in future photonic quantum networks.