Molecular ion beams: from spacecraft propulsion to ion beam etching

About the Project

Supervisory Team: Charlie Ryan and Alex Wittig

Ready to revolutionize microfabrication? Traditional gallium ion sources limit ion beam flexibility, but Ionic Liquid Ion Sources (ILIS) unleash a vast variety of ions for precision etching. Southampton’s cutting-edge PhD project, in partnership with Thermo Fisher, explores ILIS fundamentals—pioneering next-gen focused ion beam technology for unmatched etching control.

Gallium Liquid Metal Ion Sources (LMIS) are the standard choice for ion beam material etching, facilitating ion beam lithography as the go-to technique for in situ microfabrication. Many microfabrication applications would benefit though from a more flexible ion beam source, with different ion beam species significantly influencing the physical and chemical nature of the milling results, for example reducing ion implantation or enhancing etching through using chemically reactive ions.

One such option is Ionic Liquid Ion Sources (ILIS), where rather than extracting ions from a liquid metal such as gallium, molecular ions can be extracted from an ionic liquid. Through the use of ionic liquids, there is a far greater choice of ion type that can be emitted, across a much larger range, offering the ultimate flexible ion source. Recently there have been great improvement in the operation of ILIS's through the development of their use for ion thrusters for spacecraft.

Our research group at Southampton has developed an electrospray ion thruster for micro spacecraft propulsion, and have over the last several years investigated it as an etching tool, in a broad manner, as part of an EPSRC funded project.

This PhD will develop this concept further, where in collaboration with Thermo Fisher Scientific (the World lead in Focused Ion Beam systems) we will develop such a system specifically for etching processes within focused ion beam columns.

You will investigate the fundamentals of ion emission from an Ionic Liquid Ion Source, investigating the properties of the beam using various diagnostic techniques, using the excellent facilities at the David Fearn Electric Propulsion Laboratory.

The PhD studentship will focus on experimental investigating fundamental aspects of ILIS's. Particular emphasis will be put on gaining insight into the ion emission process, the use of novel ion liquids, and greater understanding of the etching process.

Training in the experimental testing of ion beams, relevant to applications including ion etching to spacecraft propulsion.

Entry requirements

You must have a UK 2:1 honours degree, or its international equivalent.

Fees and funding

We offer a range of funding opportunities for both UK and international students. Horizon Europe fee waivers automatically cover the difference between overseas and UK fees for qualifying students. Competition-based Presidential Bursaries from the University cover the difference between overseas and UK fees for top-ranked applicants.

Competition-based studentships offered by our schools typically cover UK-level tuition fees and a stipend for living costs for top-ranked applicants.

Funding will be awarded on a rolling basis, so apply early for the best opportunity to be considered. For more information, please visit our postgraduate research funding pages.

How to apply

Apply now

You need to:

• choose programme type (Research), 2026/27, Faculty of Engineering and Physical Sciences
• select Full time or Part time
• search for programme PhD Engineering & the Environment (7175)
• add name of the supervisor in section 2 of the application

Applications should include:

• your CV (resumé)
• 2 academic references
• degree transcripts and certificates to date
• English language qualification (if applicable)

Contact us

Project leader

If you wish to discuss any details of the project informally, please contact Dr Charlie Ryan (c.n.ryan@soton.ac.uk).