PhD Studentship: Experimental and Computational Studies of Si and Ge Layers on Diamond for Enhanced NEA and Solar Power Applications

University of Bristol - Faculty of Science / School of Chemistry

The project: Experimental and computational studies of Si and Ge layers on diamond for enhanced NEA and solar power applications - 4 year PhD, as part of the Diamond Science and Technology CDT (1 year at Warwick, 3 years at Bristol, start Oct 2018)

Recent experimental and theoretical work has shown that diamond terminated with suitable metal-oxides can have negative electron affinity (NEA) values that are significantly higher than those from hydrogen, and that these surfaces can be stable up to 1000 K. Such surface terminations include LiO, MgO, TiO, AlO, VO, and a range of others yet to be tested. Diamond with a suitable surface termination therefore is an excellent candidate for use in thermionic heat converters for use in solar power generators.

Recent reports suggest that sub-monolayers of Si or Ge on diamond may also improve the NEA significantly, whilst remaining air and temperature stable. This PhD is 50% experimental, 50% theoretical modelling. Experimentally, the student will use the new nanoESCA facility at Bristol, equipped with an evaporation/deposition chamber, to deposit sub-monolayers of first, Si and later, Ge, onto single-crystal diamond surfaces. The effectiveness of these surfaces as electron emission sources will then be tested both in situ in the nanoESCA facility (without breaking vacuum), and also in a bespoke thermionic test rig. The experimental work will be guided by theoretical modelling and by surface analysis such as SIMS or XPS. The modelling at Bristol will be performed by bespoke computer packages (CASTEP and CRYSTAL) which have been extensively used by the theory group at Bristol for the past decade to model diamond surfaces. For the computational side, the aims would be to simulate addition of Si or Ge atoms to a (100) diamond surface, varying the coverage from sub-monolayers to 1 ML, and by minimising the energy, predict the optimal geometries for the adsorbed species, their thermal stability, and investigate the factors that determine the resulting electron affinity.

How to apply:

Please make an online application for this project at http://www.bris.ac.uk/pg-howtoapply. Please select Chemistry PhD on the Programme Choice page and enter details of the studentship when prompted in the Funding and Research Details sections of the form

Candidate requirements: Must be a UK national.  1st class or upper-second class degree in chemistry, physics, materials, or a related subject. 

Funding: 50% EPSRC (via the CDT), 50% University of Bristol

Contact: Paul May (paul.may@bristol.ac.uk)

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Type / Role:

PhD

Location(s):

South West England