Optical properties of individual CdS/CdSe/CdS nanocrystals: spherical quantum wells as single-photon sources. (2nd July 2022)

• Record Type: Journal Article
• Authors: Allemand, A; Kulzer, F; Mahler, B; Dujardin, C; Houel, J
• Is Part Of: Nanotechnology. Volume 33:Number 27(2022)
• Publication Date: 2022-07-02
• Subjects: nanocrystals -- single photon -- CdSe/CdS; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/ac5ee3
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: We have synthesized CdS(1.3 nm)/CdSe(1.7 nm)/CdS(3.4 nm) spherical quantum wells (SQWs) with a diameter of 13 nm and demonstrated the first photon-antibunching from their emission, labelling them as single-photon sources. Antibunching survives even at high excitation intensities, ruling-out strong emission from the bi-exciton. For the largest intensities, antibunching coupled to spectral measurements reveal the signature of a blue-shifted emission, associated to an irreversible photo-aging effect. A statistical analysis over 26 SQWs demonstrates a moderate correlation between the energy of the main and the blue-shifted emission. Intensity-timetraces recorded on 28 single SQWs show weak blinking, with a median time spent in the bright state of 89%. Their emission decay reveals a complex dynamic with either three or four exponential components. We assigned three of them to the neutral and singly-charged excitons and the slowest to defect emission. While SQWs have been initially designed for laser-oriented applications, we demonstrate that they can serve as efficient single-photon sources.