PhD Studentship: Studies of Thermionic and Field Emission from Chemically Modified CVD Diamond Surfaces

University of Bristol - Faculty of Science, School of Chemistry

The project:
A 4-year PhD studentship is available at Bristol from September 2015 jointly supervised by Prof Paul May and Dr Neil Fox as part of the Centre for Doctoral Training in Diamond Science and Technology. This project comprises:

  • First 6 months is a taught MSc course studying the theory and practical aspects of Diamond Science & Technology (CDT, Warwick University)
  • 3-month miniproject learning about theoretical modelling of defects in diamond (Newcastle University)
  • 3-month miniproject studying dopants in diamond using XPS (Aberystwyth University)
  • Final 3 years PhD by research (Bristol University, diamond lab)

Hydrogenated diamond surfaces exhibit negative electron affinity (NEA) as a result of the enhanced surface dipole, which makes extracting electrons from diamond in vacuum relatively easy and efficient. The electrons can be extracted by application of a high electric field (field emission) or heat (thermionic emission), the efficiency of which depends on the magnitude of the NEA. Recent experimental work (Bristol, Arizona State Uni) and theoretical work (Bristol & Newcastle) have shown that diamond terminated with suitable metal-oxides can have NEA values that are significantly higher than those from hydrogen, and that these surfaces can be stable up to 1000K. Such oxides include LiO, MgO, TiO, TaO, VO, and a range of others yet to be tested. Metal-oxide-terminated diamond is an excellent candidate for use in thermionic heat converters for use in solar power generators. Such thermionic converters could be used in parallel with current photovoltaic cells to capture both the visible and IR (heat) portions of the solar spectrum, greatly increasing the efficiency of solar power generation.

You will deposit various metal oxides (from the list above or newly developed ones) onto diamond surfaces, and then test the effectiveness of these surfaces as electron emission sources. The experimental work, such as choice of metal-oxide, will be guided by theoretical modelling (initially as a miniproject at Newcastle, but continuing throughout the PhD) and by surface analysis such as SIMS or XPS (initially at Aberystwyth but continuing at Bristol throughout the project). The aim would be identify and study in detail an adsorbate (metal-oxide or otherwise) that would enhance the NEA of a diamond surface, be stable at high temperatures (1000K), give a high electron yield at low temperatures (600K), not degrade with use, and be suitable for use in a commercial thermionic heat convertor.

How to apply:
There are TWO applications, one to the Warwick CDT training programme (see:http://www2.warwick.ac.uk/fac/sci/dst/phd_projects/#ED for details of how to apply) and an online application for this particular Bristol-based PhD project at http://www.bris.ac.uk/pg-howtoapply. Please select Chemistry on the Programme Choice page and enter details of the studentship when prompted in the Funding and Research Details.

Candidate requirements: First or Upper-Second Class Hons degree in a relevant science subject, such as Physics, Chemistry, Materials Science, or Electronic Engineering.

Funding: UK/EU candidates receive 48-months full funding from the DST CDT EPSRC grant. Outstanding non-EU candidates may be accepted if they can provide the difference between UK and Overseas fees (£15k p.a.)

Contacts: Prof. Paul May: paul.may<στο>bristol.ac.uk

The University of Bristol is committed to equality and we value the diversity of our staff and students.

Apply