Self-formed quantum wires and dots in core-shell nanowires for quantum photonics

Abstract number
European Microscopy Congress 2020
Corresponding Email
[email protected]
PSA.3 - Semiconductors & Devices
Professor Ana M Sanchez (2), Dr H Aruni Fonseka (2), Dr A V Velichko (3), Dr Y Zhang (1), Mr James A Gott (2), Mr G D Davis (1), Dr Richard Beanland (2), Professor Hui-Yun Liu (1), Professor David J Mowbray (3)
1. University College London
2. University of Warwick
3. Unversity of Sheffield

Semiconductor nanowires, self-formed structures, segregation

Abstract text

III-V semiconductor growth on Si substrates has the potential to reduce significantly device costs but also allows the direct integration of III-V light emitters with Si electronics. Growth on Si substrates will also reduce the dependence on scarce III-V materials. Nevertheless, there are significant challenges for the integration of III-V on Silicon due to the difference in lattice parameters and expansion coefficients. Nanowires offer an ideal solution, based on their small contact area with the substrate providing better tolerance to strain and effectively expelling dislocations. Additionally, self-assembly is a powerful strategy to generate quantum structures embedded within the nanowires, providing potential applications in photonic devices. 

Nanowire morphologies make growth on different facets possible, favoring the generation of unintentional self-formed structures. Although this process can deteriorate the device performance in some cases, it has been demonstrated that these unintentional structures exhibit superior optical properties to those grown intentionally. This talk will focus on the formation and characterization of quantum wires and quantum dots at the core-shell interface of twinned GaAsP-GaAsP nanowires. Details about location and distribution of these features will be elucidated based on the nanowire characteristics, such as polarity and composition.

Optical measurements by photoluminescence confirm the quantum emitter characteristics of the self-formed structures. Thus, the possibility to control the relative formation of QWRs or QDs, and resulting emission wavelengths of the QDs, by controlling the twinning of the nanowire core, opens new possibilities for designing nanowire devices.