Fine structure of excitons in InAs quantum dots on GaAs(110) planar layers and nanowire facets

Abstract

We investigate the optical properties of InAs quantum dots grown by molecular beam epitaxy on GaAs(110) using Bi as a surfactant. The quantum dots are synthesized on planar GaAs(110) substrates as well as on the {110} sidewall facets of GaAs nanowires. At 10 K, neutral excitons confined in these quantum dots give rise to photoluminescence lines between 1.1 and 1.4 eV. Magneto-photoluminescence spectroscopy reveals that for small quantum dots emitting between 1.3 and 1.4 eV, the electron-hole coherence length in and perpendicular to the (110) plane is on the order of 5 and 2 nm, respectively. The quantum dot photoluminescence is linearly polarized, and both binding and antibinding biexcitons are observed, two findings that we associate with the strain in the (110) plane This strain leads to piezoelectric fields and to a strong mixing between heavy and light hole states, and offers the possibility to tune the degree of linear polarization of the exciton photoluminescence as well as the sign of the binding energy of biexcitons. arXiv:1704.08543v1 [cond-mat.mes-hall]

Coaxial GaAs/(In,Ga)As Dot-in-a-Well Nanowire Heterostructures for Electrically Driven Infrared Light Generation on Si in the Telecommunication O Band

“…In these experiments, only 2–3 NWs are excited simultaneously. Sharp spectral features are revealed at low excitation power density (Figure e), similar to the transitions observed for InAs QDs on GaAs NW facets Figure f shows in linear scale the spectral range marked in Figure e.…”

“…Furthermore, for the same reason the actual shape of the QDs and details like possible intermixing cannot be deduced from these data. However, studies of Bi-induced QDs grown on GaAs(110) planar surfaces and NW side walls suggest the presence of a wetting layer and a QD shape with a much larger width than height. ,, The determination of the actual In content and distribution within the QDs introduced here, as well as their precise shape, would require additional advanced microstructural characterization beyond the scope of this work. , …”

“…Sharp spectral features are revealed at low excitation power density (Figure 3e), similar to the transitions observed for InAs QDs on GaAs NW facets. 22 Figure 3f shows in linear scale the spectral range marked in Figure 3e. The spectral linewidth of the most prominent transitions is approximately 200 µeV, limited by the spectral resolution of the experimental setup.…”

“…However, studies of Bi-induced QDs grown on GaAs(110) planar surfaces and NW side walls suggest the presence of a wetting layer and a QD shape with a much larger width than height. 21,26,27 The determination of the actual In content and distribution within the QDs introduced here, as well as their precise shape, would require additional advanced microstructural characterization beyond the scope of this work. 19,28 The luminescence of the DWELL NWs is first studied by CL spectroscopy as presented in the upper part of Figure 3 (Figure 3a−d).…”

Bismuth-surfactant-induced growth and structure of InAs/GaAs(110) quantum dots

“…11 Accordingly, recent photoluminescence (PL) experiments have indicated that emission from Bi-induced (110) QDs is linearly polarized. 12 We note that historically, surfactants have mostly been used to kinetically suppress three-dimensional (3D) island formation in strained-layer epitaxy. 13,14 Here, we investigate the Bi-surfactant-induced self-assembly of InAs 3D islands on GaAs(110) by molecular beam epitaxy (MBE).…”