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Details of Grant 

EPSRC Reference: EP/M508305/1
Title: Novel Processing for Diamond Quantum Technologies
Principal Investigator: Newton, Professor ME
Other Investigators:
Researcher Co-Investigators:
Project Partners:
Department: Physics
Organisation: University of Warwick
Scheme: Technology Programme
Starts: 01 June 2015 Ends: 31 August 2016 Value (£): 95,983
EPSRC Research Topic Classifications:
EPSRC Industrial Sector Classifications:
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Panel History:  
Summary on Grant Application Form
State of the art bulk single crystal diamond material e.g. very low impurity contamination, low structural defect density,

isotopically engineered, has been realised but many quantum technologies demand near surface nitrogen-vacancy (NV)

centres "on demand" with reproducible properties approaching the best that can be achieved when positioned in the bulk of

the diamond. NV centres can be grown-in, produced by irradiation damage plus annealing where by pre-existing

substitutional nitrogen captures a mobile vacancy, or produced by nitrogen ion implantation plus annealing. In the bulk

(typically 10 mirco-m from the surface) NV centres can have exceptional quantum properties but these are typically

significantly degraded close to a surface due to subsurface damage (e.g. micro-cracks, trapped charge, parasitic spins,

strain) produced by polishing. Even though diamond can be mechanically polished (e.g. with small diamond particles

embedded in a cast iron wheel) with low surface roughness (< 1 nm), the sub-surface regions are damaged. As grown

surfaces are not sufficiently flat for many applications but current "polishing" technology significantly impairs the

performance of near surface NV centres so a new technology that can be easily transferred to production is required.

This project focuses on the implementation and optimisation of chemical mechanical polishing (CMP) of single crystal

diamond to achieve both low (<< 1 nm) surface roughness and low surface damage such that the touted supreme and

exploitable quantum properties of near surface (< 50 nm) NV centres are fully realised. Moreover, this work will facilitate the

routine production of very thin (< 30 mirco-m) large area single crystal diamond plates with optimised surface finishes.

There is considerable demand for this material for a variety of photonic and quantum technologies; here CMP is an


The research programme will provide irrefutable evidence that CMP of diamond is a quantum technology enabler.

Traditional polishing techniques such as standard resin bond and scaife polishing are known to produce different damage

profiles that affect the near surface NV centres. ICP etching is currently the standard tool used to make quantum devices

out of diamond but is also known to impart damage to the diamond. Hence, studies on NVs near to a variety of differently

polished, etched and as-grown surfaces, as well as those in the bulk will be employed to bench-mark against the CMP


Characterisation of near surface NV centres will be achieved using (i) high resolution single centre confocal

photoluminescence microscopy which enables statistical analysis of the properties of NV's e.g. probability of production,

stability, sensitivity to surface termination etc., with respect to distance from the top surface and surface processing

methodology (e.g. CMP, etching, termination etc.) and (ii) optically detected magnetic resonance, using state of the art high

through-put equipment under ambient conditions and at cryogenic temperatures. This provides information on the allimportant

spin lifetime of individual centres as a function of depth, surface preparation and processing. There is expected to be a significant statistical variation of the NVs properties due to other uncontrolled parameters on the nanoscale (i.e.

location of 13C, substitutional nitrogen, dislocations, surface spins, surface charges), hence the statistical analysis is


Near surface NV centres will be implanted (and annealed) after and before the CMP polishing process using low energy ion

implantation (via collaboration, at no cost to program, with Jan Meijer, Leipzig University) and fully characterised. Low

energy ion implantation provides the ultimate control in NV positioning ideal for device manufacture, and is an ideal way to

demonstrate that CMP can significantly improve the yield of useful near surface implanted NV centres.
Key Findings
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Potential use in non-academic contexts
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Date Materialised
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Organisation Website: http://www.warwick.ac.uk