Event Details

Condensed Matter Physics webinar

Developments in MBE technology have allowed semiconductor quantum dots (QDs) of increasingly high quality to be grown. By incorporating these high-quality QDs into photonic devices it has been shown that quantum bits (qubits) can be created and manipulated. [1] The ability to grow QDs with suitable properties, in conjunction with improving fabrication capabilities, makes the production of quantum circuits and therefore quantum computers a realistic goal. [2] However, a significant challenge remains if this goal is to be achieved, in that the use of randomly positioned QDs in these structures does not easily allow scale-up of the systems. [3] By instead using site-controlled QDs, where the nucleation positions of the emitters can be deterministically controlled using a fabricated nano-feature, a solution is presented. But, the nature of the site-control process can lead to the quality of these QDs being adversely affected. [4, 5]

In this talk I will present the methods used to scalability control the growth position of QDs and ways in which the degradation of properties, such as single QD linewidths, can be minimised. We approach site-control using an ex-situ nanohole fabrication method, which offers a route to controlling QD size and the number of QDs at each site. The fabrication and growth structures are designed to allow the arrays of QDs to be integrated into single mode photonic devices.

1. Wang et al. Nat. Photonics 14, 273–284 (2020)

2. Rodt et al. APL Photonics 6, 010901 (2021)

3. Sapienza et al. Scientific Reports 7, 6205 (2017)

4. Herranz et al. Nanotechnology 26, 195301 (2015)

5. Jöns

et al. Nano Lett. 13, 126-130 (2013)

If someone from outside of the Condensed Matter Physics group would like to join the webinar, please send a request to m.thompson@lancaster.ac.uk