Single-photon emission from InGaAs quantum dots grown on (111) GaAs

Abstract

In this letter, we demonstrate that self-organized InGaAs quantum dots ͑QDs͒ grown on GaAs ͑111͒ substrate using droplet epitaxy have great potential for the generation of entangled photon pairs. The QDs show spectrally sharp luminescence lines and low spatial density. A second order correlation value of g ͑2͒ ͑0͒ Ͻ 0.3 proves single-photon emission. By comparing the power dependence of the luminescence from a number of QDs we identify a typical luminescence fingerprint. In polarization dependent microphotoluminescence studies a fine-structure splitting ranging Յ40 eV down to the determination limit of our setup ͑10 eV͒ was observed.

Magnetic field induced valence band mixing in [111] grown semiconductor quantum dots

“…However, the corresponding contribution δg h2 ∝ δγ is indeed small and, in the case of trigonal dots, constitutes a fraction ≤ 10% of that obtained from Eq. (20). As mentioned above, an additional mechanism of the magneto-induced mixing of the ±3/2 hole states suggested in Ref.…”

“…15 This growth axis has the advantage of providing in principle quantum-dot shape of the higher C 3v point symmetry. Really, small fine structure splittings in as grown [111] quantum dot structures have been recently predicted 16,17 and observed [18][19][20][21] making such structures a very promising system for entangled photon pair emission.…”

Strain-driven growth of GaAs(111) quantum dots with low fine structure splitting

“…Instead of assembling QDs, the compressive strain relaxes plastically to form dense misfit dislocation arrays. 8,9 The failure of S-K growth on (111) surfaces has driven the development of alternative (111) QD growth techniques including droplet epitaxy [10][11][12] and growth on patterned substrates. 13,14 In droplet epitaxy, metal droplets deposited onto the substrate are crystallized under arsenic vapor to form III-V semiconductor QDs.…”

Intertwining of Zeeman and Coulomb interactions on excitons in highly symmetric semiconductor quantum dots

“…5 Most experimental studies of excitons confined in QDs were performed on self-assembled quantum dots (SAQDs) grown on {100} surfaces and were concerned with polarization anisotropy, [16][17][18] in-plane anisotropy of carrier effective g factors, 19,20 fine-structure splitting of neutral and charged exciton complexes, [21][22][23][24] which were induced by the shape asymmetry, and the existence of anisotropic strain and piezoelectric fields in these dots. Only recently, highly symmetric pyramidal QDs grown on {111} surfaces have emerged as interesting quantum structures in which zero fine-structure splitting of the neutral exciton was predicted 25,26 and eventually observed, [27][28][29][30] and for which the entanglement of polarized photon pairs was demonstrated. 31 It is our purpose in this paper to develop a general theoretical model of the Zeeman effects on the quantum states of excitons in highly symmetric QDs and to compare its predictions to experimental studies performed on magnetoexcitons confined in pyramidal QDs grown on (111)B GaAs substrates.…”