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Title: Modern quantum optics of mid gap chalcogen donors in single crystal silicon
Author: Royle, William
ISNI:       0000 0004 7962 1730
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2018
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In this thesis the reasons for pursuing an optically addressable quantum object in silicon are outlined before introducing some possible technological applications. Chalcogen donor electron systems in silicon are then discussed as a candidate for these quantum technologies. The chalcogen donor complexes in silicon allow the solid-state analogues of hydrogen and helium to be studied. The time-resolved Fourier transform technique was employed to measure the photoluminescence from a selenium doped silicon sample when pumped above band gap at the temperatures 10 K, 80 K and 300 K. The excited state lifetime of the 2p0 state was found to be 28.2 ns for atomic centres and 66.4 ns for molecular centres at 10 K. The lifetimes were seen to be similar across large emission bands indicating a rate limiting step. A multi-colour pump-probe experiment, using time-resolved Fourier transform spectroscopy, was performed at the FELIX institute to determine the excited state lifetimes of the 2p0 and 1s(T2) to be < 2.5 ns and 10.62 ns respectively. A system of 5 coupled rate equations was then implemented to verify the experimental results. The lifetimes were theoretically determined from three sets of initial conditions. Carriers were initially positioned in the conduction band, modelling the photoluminescence experiment, the 2p and 1s states, imitating the FELIX experiment. The 2p state was shown to have two decay lifetimes, one 15.1 ps and the second of 7.24 ns. The first fast decay is due to the pure 2p state relaxation while the second long lifetime is a result of the 1s(T2) state in uencing the 2p excited state lifetime. The 1s(T2) excited state lifetime that back-fills the 2p state elongates the 2p excited state lifetime, causing the lifetime to appear longer than the true lifetime. This research implies that silicon has the potential to be an accessible test bed for quantum experiments by showing that it could be possible to create isolated non-interacting donor centres that are individually optically addressable by mid-IR laser light.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QC Physics