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Introduction Surface acoustic waves SAWs have a longstanding tradition in the investigation and control of semiconductor nanostructures at radio frequencies rf [ 1 — 14 ].
Very recently, these propagating coherent phonons have been recognized as a versatile tool to control single quantum systems [ 1516 ], quantum dots [ 17 — 20 ], nitrogen vacancy centers [ 2122 ] or superconducting artificial atoms [ 23 ].
On one hand, the strain field of the SAWs enable the dynamic tuning of the QD emission energy by deformation potential coupling [ 1724 ].
On the other hand, its electric field allows carrier and spin transport and injection inside the QDs and control over their occupancy state [ 825 — 29 ].
Because of the sensitivity of the SAW propagation to mass loading and surface defects, a study of the SAW propagation within the transferred membrane is crucial, before advancing such devices to more complex systems.
Here we report such a study by analysing the propagation of the wave inside the membrane in the acousto-electric and acousto-optic domains using SAW delay lines and individual QDs, respectively.
Both effects are recorded in parallel as a function of the electrical frequency applied to the IDT.
Over this wide range of frequencies, we observe a clear increase of the optomechanical coupling parameter for the increasing frequency.
For moderately high acoustic frequencies, our simulations predict strong optomechanical coupling, making our hybrid device ideally suited for applications in semiconductor based quantum acoustics.
Sample design and methods The sample is schematically described in figure 1 a. These tailored frequency characteristics allowed for the characterisation of the SAW propagation at different frequencies. In the centre of the membrane, a layer of Ga As QDs was fabricated by a droplet etching and filling technique [ 40 ].
The membrane was subsequently transferred onto the Pd layer.
SAWs can be generated directly on III—V semiconductors and derived heterostructures, exploiting these materials' piezoelectric properties.
However, direct epitaxial growth of semiconductors on Li Nb O3 has so far for instance been achieved for 2D transition metal dichalcogenides [ 1430 ].