Data-driven Development of Calibration and High-throughput Measurement Protocols for Quantum Structures

Abstract

Repeatably quantifying optoelectronic properties of quantum photonic materials between each other is a challenge in the absence of a standard procedure or reference. This is a crucial feedback step for optimising growth, and characterising the performance of photonic modifications such as waveguides and microcavities. In many cases, an exper- imental system’s excitation and transmission efficiencies are not completely accounted for, due to the unique optics used between systems. A standard, such as a quantum reference material or measurement protocol would alleviate these issues, especially given that light coupling in to sub-micron sized samples is non-trivial and modelling is hard. In effect, this enables quantitative comparison of optoelectronic properties, outside of a local environment to a widely accepted standard. This PhD thesis is dedicated to using confocal high-throughput micro-PL and sensit- ive single-photon experimentation, for development of protocols and references for meas- uring quantum confined materials towards a wider accepted standard. This was used to show an improved radiative recombination efficiency, due to intramaterial strain, in ra- dially hosted GaAs quantum wells (QWs) in GaAs/GaAsP core/shell NWs, by probing the optoelectronic properties of >15,000 individual heterostructures. The system was also used for assessing inhomogeneity in 2D thin-film TMD samples as a contribution towards developing a standard measurement protocol. Further, part of the work involved a cross-site calibration of single-photon measure- ment systems using NVs centres hosted in nanodiamonds (NDs). This proposes that the NV centre can act as a single-photon source reference owing to its portability, stability and robustness. This can then be used for system calibration, through the empirically established relationship between pump power and single photon emission rate. This work demonstrates a framework for developing measurement standards in light of the increasing number of new photonic materials and configurations.

Date of Award	16 Dec 2024
Original language	English
Awarding Institution	The University of Manchester
Supervisor	David Binks (Co Supervisor) & Patrick Parkinson (Main Supervisor)