Site‐controlled quantum dot growth on buried oxide stressor layers

Abstract

Site-controlled growth of quantum dots (QDs) for single photon emitters (SPEs) is achieved applying a buried stressor approach. Theoretical and experimental analysis shows that site-controlled QD growth on buried oxide stressor-layers benefits enormously from a defect-free growth interface. Laterally modulated strain fields at GaAs(001) growth surfaces are used to tailor surface morphologies at the centre of prescribed mesa structures for subsequent QD growth. Suitable morphologies for site-controlled QD growth such as nano-hillocks and nanoholes are identified. Site-controlled QD growth appears above the boundaries between the oxidised layer and the non-oxidised semiconductor layer. Through fine tuning of wetting layer thickness and growth interruption high selectivity for QD nucleation is achieved. Thus, growth of single QDs at the centre of a current-injection limiting aperture is demonstrated. Moreover, the QD growth on a defect-free surface yields high quality optical properties in terms of narrow emission linewidth and temporal stability with no discernible difference to QDs grown on planar substrates. The technological simplicity of the buried stressor approach and the inherent integration of a current aperture for efficient carrier injection into site-selected QDs enable mass production of SPEs on large substrate sizes.

Charge-driven feedback loop in the resonance fluorescence of a single quantum dot

“…It consists (along the growth direction from right to left) of a highly doped, metallic GaAs back contact, a GaAs-(AlGa)As tunnelling barrier, the quantum dot layer, a GaAs spacer layer, and an (AlGa)As blocking layer. In a pre-growth etching process the sample was patterned into cylindrical mesas of ∼ 18.6 µm diameter [27,28]. Lithographically defined contacts on top of a single mesa allow for controlling the electric field at the quantum dots by applying a gate voltage.…”

Crystallographic dependent in-situ CBr4 selective nano-area etching and local regrowth of InP/InGaAs by MOVPE

“…Selective area growth (SAG) on a nanometer scale represents enormous potential for the fabrication of novel devices such as ultra-compact photonic crystal (PhC) cavity lasers with the lowest power consumption [1,2] or single photon emitters consisting of an individual QD as an active medium [3]. In addition, precise positioning of the active material gives an opportunity for the demonstration of multi-functional integrated photonic circuits.…”

Resonance fluorescence of a site-controlled quantum dot realized by the buried-stressor growth technique

“…Other approaches based on SCQDs in non-planar sample geometries such as QDs embedded in nanowires have shown promise regarding the optical quality of the QDs 17 but offer challenges regarding their scalability and integrability. Another promising technology platform for the realization of site-controlled QDs in planar sample geometries is based on a buried stressor 18,19 . In this approach, strain-tuning by a oxide-aperture leads to the localized formation of QDs where the number of site-controlled QDs can be controlled by the diameter of the aperture 19,20 .…”

“…Another promising technology platform for the realization of site-controlled QDs in planar sample geometries is based on a buried stressor 18,19 . In this approach, strain-tuning by a oxide-aperture leads to the localized formation of QDs where the number of site-controlled QDs can be controlled by the diameter of the aperture 19,20 . The approach provides a pristine growth surface fairly separated from the stressor and, thus, promises high optical quality of the localized QDs.In this letter, we report on optical and quantum optical properties of single QDs grown on a buried-stressor under strict resonant excitation.…”