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arXiv · 2507.06058

Spin properties in droplet epitaxy-grown telecom quantum dots

Marius Cizauskas·Elisa M. Sala·Jon Heffernan·A. Mark Fox·Manfred Bayer·Alex Greilich
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Abstract

We investigate the spin properties of InAs/InGaAs/InP quantum dots grown by metalorganic vapor-phase epitaxy (MOVPE) deposition using droplet epitaxy, which emit in the telecom C-band. Using pump-probe Faraday ellipticity measurements, we determine electron and hole $g$-factors of $|g_e| = 0.934$ and $|g_h| = 0.471$, with the electron $g$-factor being nearly twice as low as typical molecular beam epitaxy Stranski-Krastanov (SK) grown samples. Most significantly, we measure a longitudinal spin relaxation time $T_1 = 2.95\,\mu s$, representing an order of magnitude improvement over comparable MBE SK grown samples. Despite significant electron $g$-factor anisotropy, we observed that it is reduced relative to similar material composition samples grown with MBE or MOVPE SK methods. We attribute these g-factor anisotropy and spin lifetime improvements to the enhanced structural symmetry achieved via MOVPE droplet epitaxy, which mitigates the inherent structural asymmetry in strain-driven growth approaches for InAs/InP quantum dots. These results demonstrate that MOVPE droplet epitaxy-grown InAs/InGaAs/InP quantum dots exhibit favorable spin properties for potential implementation in quantum information applications.

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Marius Cizauskas, Elisa M. Sala, Jon Heffernan, A. Mark Fox, Manfred Bayer, Alex Greilich. 2025-07-08. Spin properties in droplet epitaxy-grown telecom quantum dots. https://doi.org/10.1103/bm22-smcp

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