Speaker
Description
III-V quantum dots (QDs) act as naturally bright and highly efficient quantum emitters that can generate deterministic single or entangled photon pairs. QDs embedded in a free-standing nanowire (NW) serve as a scalable platform for site-selective and geometry-controlled in-situ heterogeneous integration onto photonic waveguides (WG) - a crucial milestone for the realization of a quantum photonic integrated circuit.
The first part briefly shows, by numerical modelling, how geometrical parameters of a NW and Si-WG design influence the spontaneous emission enhancement of the QD emitter and the in-coupling efficiencies at the NW-WG interface [1]. Ongoing experiments towards the development of an integrated III-V NW-QD system are then presented. Using entirely catalyst-free site-selective molecular beam epitaxy (MBE), we first established the growth of the vertical-cavity GaAs(Sb) NW waveguide directly on silicon, which exhibits high-quality microstructure and optical properties mediated by the Sb surfactant effect [2]. Here, tuning Sb incorporation over a narrow compositional range (Sb~1.5–6%) was found to be a crucial parameter in tailoring also the growth- and exciton dynamics in the NW material [3]. The non-catalytic, droplet-free MBE growth opens further suitable pathways for pristine axial NW heterostructures, as evidenced by abrupt GaAs(Sb)/InGaAs axial heterointerfaces and their distinct luminescence features [4]. Furthermore, to tune the emission properties, Indium incorporation as well as the size of the InGaAs axial segment are calibrated, systematically progressing towards an axial QD. These results indicate great potential towards the deterministic construction of III-V quantum emitters on silicon photonic integrated circuits.
References
[1] N. Mukhundhan, et al., Opt. Express 29, 43068 (2021).
[2] A. Ajay, H. W. Jeong, et al., Appl. Phys. Lett. 121, 072107 (2022).
[3] H. W. Jeong, et al., Small 19, 2207531 (2023).
[4] H. W. Jeong, et al., in preparation (2023).
| Keywords | Semiconductor, Nanowire, Quantum Dot, Quantum Light Source, Silicon Photonics, Molecular Beam Epitaxy |
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