Professor Robert Taylor

Abstract:

The data was taken with temperature-dependent time-integrated, time-resolved, and polarisation-resolved microphotoluminescence, and Hanbury Brown and Twiss experiments from 5 to 250 K. The purpose is to investigate whether non-polar a-plane quantum dots can act as high temperature single photon sources with optical polarisation control beyond the 200 K Peltier cooling threshold. All data were taken during April-May 2016.

Abstract:

The data were created from k.p simulation, polarization-resolved microphotoluminescence, and Hanbury Brown and Twiss experiments, from 2015 to 2016. The data were created to demonstrate the rigorous generation of polarised single photons with a deterministic axis, and to explain the origin of high polarisation degree and fixed axis, in a-plane InGaN quantum dots. All data were hence used in Figures 2-5 in the publication “Direct generation of linearly polarized single photons with a deterministic axis in quantum dots”

Abstract:

Creation: 11.2016-1.2017 Raw data + analysed data by Matlab and Origin For each figure the rawdata underlying it was added as well.

Abstract:

Exfoliated crystalline niobium oxides that contain exposed but interconnected NbO 6 octahedra with different degrees of structural distortion and defects are known to catalyze Brønsted acid (BA), Lewis acid (LA), and photocatalytic (PC) reactions efficiently but their structure–activity relationships are far from clear. Here, three exfoliated niobium oxides, namely, HSr 2 Nb 3 O 10 , HCa 2 Nb 3 O 10 , and HNb 3 O 8 , are synthesized, characterized extensively, and tested for selected BA, LA, and PC reactions. The structural origin for BA is associated mainly with acidic hydroxyl groups of edge-shared NbO 6 octahedra as proton donors; that of LA is associated with the vacant band position of Nb 5+ to receive electron pairs from substrate; and that of PC is associated with the terminal Nb=O of NbO 6 octahedra for photon capture and charge transfer to long-lived surface adsorbed substrate complex through associated oxygen vacancies in close proximity. It is believed that an understanding of the structure–activity relationships could lead to the tailored design of NbO x catalysts for industrially important reactions.

Abstract:

We demonstrate single photon emission from self-assembled m-plane InGaN quantum dots (QDs) embedded on the side-walls of GaN nanowires. A combination of electron microscopy, cathodoluminescence, time-resolved µPL and photon autocorrelation experiments give a thorough evaluation of the QDs structural and optical properties. The QD exhibits anti-bunched emission up to 100 K, with a measured autocorrelation function of g^((2) ) (0) = 0.28 (0.03) at 5 K. Studies on a statistically significant number of QDs show that these m-plane QDs exhibit very fast radiative lifetimes (260 ± 55 ps) suggesting smaller internal fields than any of the previously reported c-plane and a-plane QDs. Moreover, the observed single photons are almost completely linearly polarized aligned perpendicular to the crystallographic c-axis with a degree of linear polarization of 0.84 ± 0.12. Such InGaN QDs incorporated in a nanowire system meet many of the requirements for implementation into quantum information systems and could potentially open the door to wholly new device concepts.