Dr Cuenca develops a new methodology for fast dielectric charactersiation of diamond
A fast and easy to use split dielectric microwave resonator has been developed for X-band dielectric measurement of free-standard diamond materials. The approach can rapidly reveal stark differences in dielectric losses between samples that seem similar in Raman spectroscopy and other techniques. In particular it shows that samples grown with oxygen at Cardiff Diamond Foundry exhibit very high loss tangent.
Further developments in coherence time of nanodiamond particles
The continuing collaboration with University of Warwick (Morley group) and now Element Six has led to further improvements in the coherence times of nanodiamond particles. High quality 12C enriched polycrystalline diamond grown by Element Six was milled and purified by Cardiff Diamond Foundry. T1, T2 and T2* Coherence times of 4.3 ms, 786 µs and 2 µs respectively were recorded by the Morley Group.
Dr Leigh extends in-situ Spectroscopic Ellipsometry to Aluminium Nitride
Will Leigh builds a second comprehensive model for the in-situ monitoring of diamond growth on Aluminium Nitride via Spectroscopic Ellipsometry.
CDF demonstrates high temperature micro-hotplates in collaboration with 4K-MEMS
New micro-hotplate structures have been fabricated from boron doped polycrystalline diamond. These devices can reach temperatures over 2700 K and exhibit millisecond response times. At such record breaking temperatures the devices ultimately fail catastrophically, but they can be operated reproducibly at lower temperatures and offer a new high speed heating stage for electron microscopy, biological sensing etc:
CDF demonstrates new in-situ monitoring approaches for diamond growth
Two new papers from CDF show in-situ monitoring approaches for diamond Chemical Vapour Deposition. In one we demonstrate the mapping of pyrometry using a galvonometer. This generates accurate 2D temperature maps that we were able to verify ex-situ by mapping the film thickness and diamond quality using spectroscopic ellipsometry and Raman mapping. In a second we demonstrate the monitoring of the early stages of diamond growth by spectroscopic ellipsometry. In this paper we build a comprehensive model that we verify ex-situ by Raman spectroscopy and Atomic Force Microscopy.
Superconducting diamond coplanar resonators demonstrated
A coplanar waveguide resonator has been fabricated from superconducting nano crystalline diamond and simulated using finite element modelling. The devices exhibit higher kinetic inductance and penetration depth than single crystal diamond due to he high granularity of the nanocrsytalline diamond. This open access paper demonstrates the potential for granular B-NCD for high quality factor superconducting microwave resonators and highly sensitive kinetic inductance detectors.
Nanodiamond coated quartz filters outperform commercial electropositive filters
CDF demonstrates that nanodiamond coated quartz filters have higher positive zeta potential over a larger pH range than commercially available electropositive filters. The nanodiamond coated filters also demonstrate superior dye retention.
Ultra-low insertion loss Surface Acoustic Wave Devices demonstrated
New SAW devices fabricated by Universidad Politécnica de Madrid (UPM) demonstrate ultra - low insertion loss. The diamond was grown and plagiarised at CDF whereas the AlScN piezoelectric at UPM. The results are published in (open access) Micromachines:
Nano-SQUIDs demonstrated using Cardiff Diamond Foundry films
La Trobe University, the University of Melbourne and Cardiff University develop nanoscale superconducting quantum interference devices (nano-SQUIDs) with Dayem bridge junctions. Physical loop sizes of 50 nm were engineered in boron-doped nanocrystalline diamond films using precision Ne-ion beam milling.
Record breaking T2 times demonstrated with diamond nanoparticles
Nitrogen Vacancy centres in nanoparticles made by Cardiff Diamond Foundry’s milling of high purity Element6 single crystal diamonds have been shown by the University of Warwick (Morley group) to exhibit T2 times exceeding 400µs.
Dr Jerome Cuenca models diamond Chemical Vapour Deposition systems
Dr Cuenca verifies complex finite element models of commercial clamshell diamond CVD reactors with exhaustive experimental data. The resulting model can be used to develop substrate holders, predicting their temperature and plasma uniformity. This is a huge time and cost saver.
Microwave plasma modelling in clamshell chemical vapour deposition diamond reactors
Dr Soumen Mandal integrates diamond with Gallium Oxide
By measuring the streaming (zeta) potential of Gallium Oxide, the self assembly of diamond nanoparticles onto Gallium Oxide wafers is demonstrated.
Scott Manifold optimises contacts to superconducting diamond
Transmission Line Model (TLM) measurements were performed on various contact structures down to cryogenic temperatures.
Henry Bland demonstrates virus filtration using nanodiamond particles
Cardiff Diamond Foundry demonstrates log6.2 (>99.9999%) removal of virus from water by modifying quartz filters with hydrogenated diamond nanoparticles. The approach is cheap and robust. We are currently assessing the efficacy of the same filter for air filtration of air-born aerosolised viruses.
Dr Jerome Cuenca measures and models wafer bow / stress in diamond / III-N membranes
Large tensile stresses in diamond III/V heterostructures are characterised by Raman spectroscopy and profilometry. The stress originates from large differences in thermal expansion coefficients and are modelled with COMSOL. Wafer bow is a key issue in the integration of diamond with III-V semiconductors and this work proposes methods to alleviate this,
Dr Georgina Klemencic explains anomalous transport behaviour in superconducting diamond with phase slips
The microstructure of boron doped superconducting nanodiamond leads to arrays of Josephson Junctions and one-dimensional like behaviour. Switching between superconducting states is demonstrated by application of electromagnetic pulses. See paper for details:
CDF awarded EPSRC “New Horizon” grant for high temperature devices fabricated from Ultra High Temperature Ceramics
CDF awarded Ser Cymru Tackling Covid19 funds for “Active Virus Filtration Membranes”
CDF developers new SiC interlayers for the growth of diamond on AlGaN with with University of Bristol, University of Glasgow and University of Cambridge.
Thin crystalline SiC inlayer provide enhanced adhesion and lower thermal barrier resistances between the diamond and AlGaN. See below paper for details:
Interview with BBC Wales “Science Café” on crystals and diamond growth, 18/6/20 18:30, also available on BBC Sounds as podcast.
“Diamond – not all that glitters is gold”, Pint of Science (filmed for BBC Wales & S4C) 16/5/18.
CDF Interview on Sky News about Lab gems, 3/5/18:
Quoted in article in Daily Mail 3/5/18
Quoted in article in Daily Express 3/5/18
Article on Wales online
CDF featured in Financial Times article on lab grown diamonds: “Spot the difference: why DIY diamonds pose a threat to big miners”
CDF work featured in Logitech eBook of case studies
Our diamond polishing work has been featured in Logitech’s eBook of customer case studies, read the full article here . More detail of our Chemical Mechanical Polishing process can be found here .
CDF interview in “Secret History of Jupiter”, Series 2, Episode 6 of “Space’s Deepest Secrets” (Science channel) and “Strip the Cosmos” (Discovery).
kSA MOS installed
We have taken delivery of a k-Space Associates MOS system. The MOS monitors the reflection of multiple parallel laser beams off the growth substrate to measure wafer curvature. We have installed this on our Carat systems CTS6U CVD reactor which allows us to monitor stress in-situ. This is a unique capability of Cardiff Diamond Foundry and can be combined with our Spectroscopic Ellipsometry.
Anton Paar SurPASS 3 aquired
We have installed an Electrokinetic analyser so we are now able to measure the streaming potential of almost any substrate. This allows us to optimise diamond nucleation on novel materials such as GaN as well as study surfaces in solution.
Carat systems CTS6U operational
Our Carat Systems CTS6U deposition system for high purity intrinsic diamond is finally operational. This system is an enhanced 6500 design with conflat sealed windows as well as differentially pumped main seals. It is capable of ppb level nitrogen levels.
Quantum Design PPMS installed
We have recently installed a new Physical Property Measurement System (PPMS) from Quantum design (Evercool II). Funded by our ERC consolidator grant. This system includes a 9T magnet with DC Magnetism, AC Susceptibility, Resistivity, Vibrating Sample Magnetometer etc. This extends our dilution refrigerator (BlueFors 7mK) capabilities for low temperature characterisation of our superconducting diamond. We also operate a unique high frequency VSM designed and built by Sean Giblin.
WASPS Poised to Bring Tunable Sources for Quantum Communications
The European Commission-funded Wavelength-tunable Advanced Single Photon Sources (WASPS) program aims to develop a new generation of triggered single-photon sources based on diamond defects coupled to novel optical resonators. The devices in development promise a range of high specifications including ambient-temperature operation, making them ideal for commercial and industrial settings. The three-year program (running from November 2013 to October 2016) involves a consortium of six European research groups.
The WASPS consortium comprises research groups at Oxford University, Bristol University and Cardiff University in the U.K.; Saarland University in Saarbrücken, Germany and Ludwig Maximilians University in Munich; and the National Center for Scientific Research (CNRS) in Grenoble, France. Construction and testing of the devices are being led by professor Jason Smith in Oxford, professor John Rarity in Bristol, professor Dr. Christoph Becher in Saarbrücken and Dr. David Hunger in Munich. Dr. Oliver Williams leads the Cardiff team, which synthesizes the defect-containing diamond materials by using chemical vapor deposition, and Dr. Alexia Auffèves at CNRS in Grenoble leads the theoretical treatment of the devices.
European Research Council awards Consolidator Grant to CDF
Oliver Williams, Principal Investigator of Cardiff Diamond Foundry has been awarded a Consolidator grant of €2.73M for the development of “Superconducting Diamond Quantum Nano-Electro-Mechanical Systems.
Coherent Anti-Stokes Raman Spectroscopy of Nanodiamond particles
A recent collaboration with Prof Langbein in Physics, Prof Borri’s group and collaborators within Cardiff Biosciences has lead to the development of Coherent Anti-Stokes Raman Spectroscopy of Nanodiamond particles. See here.
New “Nanodiamond” book published by RSC, edited by Oliver Williams
“The exceptional mechanical, optical, surface and biocompatibility properties of nanodiamond have gained it much interest. Exhibiting the outstanding bulk properties of diamond at the nanoscale in the form of a film or small particle makes it an inexpensive alternative for many applications.
Nanodiamond is the first comprehensive book on the subject. The book reviews the state of the art of nanodiamond films and particles covering the fundamentals of growth, purification and spectroscopy and some of its diverse applications such as MEMS, drug delivery and biomarkers and biosensing. Specific chapters include the theory of nanodiamond, diamond nucleation, low temperature growth, diamond nanowires, electrochemistry of nanodiamond, nanodiamond flexible implants, and cell labelling with nanodiamond particles.
Edited by a leading expert in nanodiamonds, this is the perfect resource for those new to, and active in, nanodiamond research and those interested in its applications.”