Efficient semiconductor quantum light sources

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The generation of quantised light states is a driving technology for applications of quantum devices for cryptography, sensing, imaging and computing. These research areas are funded by a UK Government Investment in excess of £600M over 10 years, aimed at accelerating the translation of quantum technologies into the marketplace. Semiconductor light sources that emit photons one-by-one, so called single photon sources, have been reported in quantum dots in Gallium Arsenide, defects in Gallium Nitride and Diamond and 2-D semiconductors, such as hexagonal Boron Nitride. The emitters operate across the visible and IR range, with different emission patterns, making direct comparisons non-trivial. The most advanced technology, InAs quantum dots, are now available from several start-up companies, each claiming high efficiency and brightness.This project will develop novel light sources and determine their efficiency, with a view to creating a "checklist" for this measurement. Recently, standardised efficiency measurements have been introduced into research on solar cells by the prestigious Nature publishing group, enforcing a "checklist" that must be reported before claiming an efficiency in any publication. This project will identify the key measurements required to report efficiency of single photon sources, independent of material, wavelength and measurement system, which may be reproduced in separate laboratories.The project will have access to single photon sources under study in Cardiff, such as quantum dots, 2D materials and wide bandgap semiconductors. Processing will occur in the university's Institute for Compound Semiconductor Cleanroom to create nanocavities and dielectric antennae. Optical measurements will occur in a newly installed lab at Cardiff and the UK's national standardisation institute, the National Physical Laboratory.