SKM 2021 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 18: Quantum Dots and Wires (joint session HL/TT)

HL 18.4: Talk

Thursday, September 30, 2021, 14:30–14:45, H4

Quantum Efficiency and Oscillator Strength of InGaAs Quantum Dots for Single-Photon Sources emitting in the Telecommunication O-Band — •Jan Große¹, Paweł Mrowiński^1,2, Nicole Srocka¹, and Stephan Reitzenstein¹ — ¹Technische Universität Berlin, Institute for Solid State Physics, Hardenbergstraße 36, 10623 Berlin, Germany — ²Laboratory for Optical Spectroscopy of Nanostructures, Wrocław University of Technology, Wybrzeze Wyspiańskiego 27, Wrocław, Poland

We demonstrate experimental results based on time-resolved photoluminescence spectroscopy to determine the oscillator strength and the internal quantum efficiency (IQE) of InGaAs quantum dots (QDs) capped by a strain-reducing layer [1] which have been used in single-photon sources (SPS) emitting in the telecom O-Band [2]. The oscillator strength and IQE are evaluated by determining the radiative and non-radiative decay rate under variation of the optical density of states at the position of the QD [3]. We measure a QD sample with different thicknesses of the capping layer realized by a controlled wet-chemical etching process. From numeric modelling the radiative and nonradiative decay rates dependence on the capping layer thickness, we determine an oscillator strength of 24.6 * 3.2 and a high IQE of about (85 * 10)% for the long-wavelength InGaAs QDs [4].

[1] J. Bloch et al., Appl. Phys. Lett. 75, 2199 (1999). [2] A. Musiał et al., Adv. Quantum Technol. 3, 2000018 (2020). [3] J. Johansen et al., Phys. Rev. B 77, 073303 (2008). [4] J. Große et al, arXiv:2106.05351 (2021).