Quantum-limited holographic sensing of nanoparticles in plasma CVD of quantum devices

Solid state device fabrication underpinning semiconductor and quantum technology [1] relies heavily on etching and deposition techniques based on plasma chemical vapour deposition (CVD) [2,3].

Any nanoparticle (NP) formation within the plasma, followed by their deposition on the device surface can lead to device failure. However, there are no suited techniques enabling detection of such NPs in real time in the plasma, hindering process optimisation, real-time monitoring and quality control. In this project you will develop and test such techniques, based on optical imaging. Two methods will be used providing complementary capabilities, both of which are quantum limited by the photon shot-noise and use the wave-particle duality of photons.

The first method is based on digital holography [4] and measures NPs in three-dimensional space, in situ in the plasma volume. The scattered photon wavefunction will be measured in amplitude and phase by interference with coherent reference photons, shot-noise limited by off-axis holography, allowing to measure the position, size, and shape of each individual NP in the volume. The second method detects NPs deposited on a surface, using the photon reflection or transmission phase and amplitude [5,6]. After developing the methodology, including setting up hardware and software, the quantum-limited detection sensitivities will be established, and reference samples will be characterised. The methods will then be tested in plasma CVD systems in real world applications at the partner site of Oxford instruments plasma technology in Bristol.

The outcome will be a real time monitoring and optimisation of the process which, beyond producing scientific publications, will have significant impact for device manufacturing. 

The student will be embedded in a vibrant multi-disciplinary research environment. The supervisory team combines strong track records in advanced optical microscopy technologies (Langbein-Borri), and CVD (Ellis). The student will access cutting-edge instrumentation and computing facilities at Cardiff University.

The student will be trained in optical microscopy, optical design, data acquisition and analysis. They will present at national/international conferences, improving their communication skills, and will benefit from training in transferable skills offered by the Doctoral Academy.

The student will be introduced to the AREA principles of Responsible Research & Innovation including relevant legal ethical frameworks. They will attend mandatory workshops covering publication ethics and responsible research behaviour. They will be introduced to the Cardiff University Code of Practice for Research Degrees to understand their rights and obligations toward responsible research.

How to apply:

Applicants should apply to the Doctor of Philosophy in Physics and Astronomy with a start date of April 2025.

Applicants should submit an application for postgraduate study via the Cardiff University webpages to (https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/physics-and-astronomy) including: 

• your academic CV 

• Your degree certificates and transcripts to date including certified translations if these are not in English 

• a personal statement/covering letter 

• two references (applicants are recommended to have a third academic referee, if the two academic referees are within the same department/school). Your references can be emailed by the referee to [email protected]  

Please note: We are do not contact referees directly for references for each applicant due to the volume of applications we receive.     

Candidates should hold or expect to gain a first-class degree or a good 2.1 (or their equivalent) in, Physics, Engineering or a related subject.

Applicants whose first language is not English are normally expected to meet the minimum University requirements (e.g. IELTS 6.5 Overall with 5.5 minimum in sub-scores) (https://www.cardiff.ac.uk/study/international/english-language-requirements) 

In the “Research Proposal” section of your application, please specify the project title and supervisors of this project and copy the project description in the text box provided.

In the funding section, please select that you will not be self-funding and write that the source of funding will be EPSRC. 

Once the deadline for applications has passed, we will review your application and advise you within a few weeks if you have been shortlisted for an interview. 

Please note we reserve the right to close this advertisement early if we receive a high volume of suitable applications.

Eligibility :

This studentships are available to home students only. Applicants should satisfy the UKRI eligibility requirements.

For more information, or if there are any questions re application process, please contact Physics and Astronomy PGR Student Support team at [email protected]