Exploring quantum emitters formation via correlative light-electron micro-spectroscopy

Light sources which emit one and only one photon on demand, known as single-photon source (SPS) are a potential building block for quantum cryptography schemes and next-generation sensing technologies underpinning our secure communications and advanced healthcare. Producing room-temperature operating SPS by exploiting the defect centers in solid-state materials, also known as colour centers, offers a promising opportunity that could bring the quantum information revolution closer to reality. A major challenge in the large-scale manufacturing of SPS is the ambiguous understanding of their origin and formation mechanisms. This PhD studentship aims to address this issue. 

Currently, the most common method for locating a single photon colour centre is through optical micro-spectroscopy using the Hanbury Brown and Twiss (HBT) interferometer. This involves measuring the joint probability of detecting a photon at one detector at time t1 and another photon at the other detector at time t2. Our proposed approach will use a similar HBT setup but with a focused ion beam scanning electron microscope. This will enable us to locate the emitters with greater accuracy. We will also use other non-destructive imaging techniques, namely cathodoluminescence hyperspectral imaging and electron channelling contrast imaging to examine colour centers. We’ll follow this with in-situ thin film lamella preparation using focused ion beams for further atomic imaging using an aberration-corrected scanning transmission electron microscope to pinpoint the origin of colour centers in III-nitrides, the material of interest. Maturity in producing large-area wafers and established integrated circuit processing make this material system a top contender for building new quantum computing architectures. 

We seek a PhD student to unravel the mysteries of colour centers in III-nitrides with our cutting-edge ultrafast multimodal micro-spectroscopy facilities at Cardiff. The student will develop novel photonic structure fabrication procedures and experimental protocols for validating any correlation between a specific defect and an SPS using the state-of-the-art facilities at the QMAT and CST research groups. This fundamental research project is outside the scope of compound semiconductor manufacturing CDT.The student will gain a wealth of experimental and analytical experience that is applicable throughout the emerging quantum technologies sector. They will also have the opportunity to work with the cross-faculty team of chemists, physicists, and electrical engineers in the College of Physical Sciences. The student will also be encouraged to interact with our UK academic collaborators and industrial partners in Europe. 

How to apply:

Applicants should apply to the Doctor of Philosophy in Physics and Astronomy with a start date of 1st October 2025. 

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

• your academic CV (Guidance on CVs for a PhD position can be found on the FindAPhD website)

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

• a personal statement/covering letter 

Ensure your personal statement (as part of the university application form, or as a separate attachment, if you prefer) provides a clear explanation of your research interest, preparation undertaken, and an understanding of the project. 

Your personal statement should be no more than 500 words, and address the following questions:

1. What are your scientific research interests and ambition?

2. How has your academic and/or professional journey prepared you for PhD study? (for instance, give examples of work you particularly enjoyed, of challenges you overcame, of connecting with others about your work or ideas, of showing inventiveness, of developing new skills and knowledge)

3. Why do you think this project is important?”

• 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 physics-admissions@cardiff.ac.uk  

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 Engineering, Physics or a related subject. Desirable skills are knowledge of Quantum Physics, Optics, Semiconductors, Technology, Physics, Engineering.

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. 

Eligibility :

This studentships are available to home and international students. International students will not be charged the fee difference between the UK and international rate. 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 Physics-PG@cardiff.ac.uk