Abstract
We report on the optical properties of single InAs/GaAs quantum dots emitting near the telecommunication O-band, probed via Coulomb blockade and non-resonant photoluminescence spectroscopy, in the presence of external electric and magnetic fields. We extract the physical properties of the electron and hole wavefunctions, including the confinement energies, interaction energies, wavefunction lengths, and $g$-factors. For excitons, we measure the permanent dipole moment, polarizability, diamagnetic coefficient, and Zeeman splitting. The carriers are determined to be in the strong confinement regime. Large range electric field tunability, up to 7 meV, is demonstrated for excitons. We observe a large reduction, up to one order of magnitude, in the diamagnetic coefficient when rotating the magnetic field from Faraday to Voigt geometry due to the unique dot morphology. The complete spectroscopic characterization of the fundamental properties of long-wavelength dot-in-a-well structures provides insight for the applicability of quantum technologies based on quantum dots emitting at telecom wavelengths.
Highlights
Single quantum dots grown by molecular beam epitaxy are one of the most promising sources of nonclassical light due to their stable and sharp emission lines and easy integration on a chip via the mature III-V semiconductor fabrication technology
A cross-section transmission electron microscopy (TEM) image of a DWELL layer grown under similar conditions is shown in Ref. [11]
Examples of the spectra collected for the negatively charged exciton in the Faraday configuration are shown in Fig. 4(a): the emission line in the presence of the magnetic field is split by the so-called Zeeman splitting [see Fig. 4(b)] with a magnitude E given by E = gμB B, where μB is the Bohr magneton and g is the Landefactor
Summary
Single quantum dots grown by molecular beam epitaxy are one of the most promising sources of nonclassical light due to their stable and sharp emission lines and easy integration on a chip via the mature III-V semiconductor fabrication technology. Since quantum dots emitting around 1300 nm are physically larger and have a higher In composition than shorter-wavelength quantum dots, the different composition and morphology can result in a different wave function extension and electron-hole overlap, impacting their fundamental response to applied fields. In this direction, analysis of the emission properties of quantum dots emitting at wavelengths >1.2 μm in the presence of an external magnetic field [17,18,19] and of 1300 nm quantum dots in the presence of external strain [11] have been reported. We measure the permanent dipole moment, polarizability, diamagnetic coefficient, and Zeeman splitting
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