Focus Issue on Site-Controlled Quantum Dots and Point Defects

Devices based on individual self-assembled semiconductor quantum dots (QDs) are promising building blocks for future photonic quantum technologies, including quantum cryptography and aspects of quantum computation. Such QDs can act as quantum emitters with near-ideal characteristics in terms of on-demand emission of indistinguishable photons and entangled photon pairs with small emission linewidths. However, establishing control over the positioning of these QDs remains challenging; well-established self-assembly routes, such as exploitation of the Stranski-Krastanov growth mode, lead to randomly-positioned structures, rather than regular arrays, hindering mass-production of devices and integration into photonic systems.

A variety of approaches have been explored attempting to overcome this challenge, including pre-patterning of the surface on which the QDs self-assemble, insertion of buried stressors below that surface or post-growth treatments of the self-assembled and capped QD material. Meanwhile, direct lithography of the QDs, bypassing self-assembly is also being investigated. Meanwhile, point defects in semiconductors are being increasingly considered as an attractive alternative to QDs in terms of the development of quantum light sources, and methods for the control of their location are thus also being explored.

Different approaches to site control have contrasting strengths and weaknesses, in terms of the accuracy and reproducibility of spatial positioning, the uniformity of properties of the QDs or defect emitters, the spectral quality of their emission and the ease of integration into standard manufacturing processes. This focus collection will explore both established and emerging approaches to the site-control of quantum emitters in semiconductors and the applicability of the various methods to a range of applications in quantum technology and beyond.

We encourage submissions from all authors whose work fits with the scope of this focus collection. The collection will also feature invited contributions. All focus issue articles are subject to the same review process as regular articles. Authors are invited to contact one of the guest editors, or the journal team directly, to discuss the suitability of their work prior to submission.

Please submit your article via our online submission form. You should submit the appropriate article type for your submission then choose 'Focus Issue on Site-Controlled Quantum Dots and Point Defects' from the drop-down menu.

The target deadline for submissions is 31^st October 2024 though we can be flexible where necessary. We encourage early submission where possible, as articles will be published on acceptance without being delayed by other papers in the collection.

MQT is pleased to offer a full waiver of the APC until the end of 2024, meaning that any submissions made before the end of 2024 will be published Open Access at no charge.