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Benjamin Hourahine
Lecturer

Benjamin Hourahine

Ben graduated with a combined degree in Chemistry and Physics in 1996 from the University of Exeter followed by a PhD in theoretical physics at the group of Prof. R. Jones. The topic of his doctoral reseach was hydrogen related defects in silicon and this has been one of his on-going research interests. After graduating in 2000, he continued for three years as a post-doc in Exeter, working within the AIMPRO consortium in Bob's group, continuing to investige hydrogen impurities. He then moved to the university of Paderborn as part of the RENiBEl European network. During this time he extended the Paderborn group's noted semi-empirical technique, DFTB to treat lanthinide impurities in semiconductors. In 2004 he then moved to work with Kevin O'Donnell (the coordinator of RENiBEl) at the Department of Physics, Strathclyde University, initially as a three year Royal Society of Edinburgh BP fellow (Modern Theory for Optoelectronics Materials), then overlapping with a Scottish Universities Physics Alliance appointment as a lecturer in optoelectronic materials in 2006.

| e: benjamin.hourahine at strath.ac.uk | t: 2325 | u: http://ssd.phys.strath.ac.uk/ |

Research

Most of Ben's research is focussed on understanding defects in semiconductors – this is where most of the interesting things happen in these materials (crystals start melting from defects, transitors and light emitting diodes only work because of engineered defects…).

His early work was on hydrogen related defects in silicon. Hydrogen is one of the most important and ubiquitous impurities in this material, and is introduced at almost every stage and step of manufacture and processing of commercial material. Water impurities lead to incorporation of H during growth, while processing steps such as plasma and chemical etching or the SmartCut process for producing silicon on insulator wafers all rely on hydrogen for their effectiveness. Additionally, hydrogen is directly included into silicon by plasma based etching or passivisation methods.

Inside of silicon, hydrogen can form H2 molecules, cover extended internal surfaces (called platelets) and stick to various other defects (including vacant sites, extra Si atoms and all manner of impurities).

hydrogen containing platelet in silicon

(111) hydrogen containing platelet in silicon. The space between the planes is filled with a high pressure phase of molecular hydrogen

More recently he has become interested in nitride semiconductors, in particular, optically important defects in these materials. Blue light emitting diodes are everywhere these days (its not futuristic if it doesn't have a blue light on it…), but surprisingly we still don't understand exactly how this material works. We know its due to indium disolved inside the crystal, but there are on-going arguments as to whether this is clumped together or spread out in the crystal. Ben moved to this field via working on rare-earths in gallium nitride, where the idea is to use these impurities to get bright red (europium), green (erbium) and blue (thulium) light emission. This family of impurities can also be used to make magnetic semiconductors.

Highlights

  • Co-organiser of `Emerging trends in Nanostructures and Nanophotonics' meeting (2007)
  • Visiting Prof. at the Dept. of Chemistry, Duke University (May 2007)
  • Guest Prof. at the Bremen Center for Computational Materials Science (May 2008)
  • Royal Society of Edinburgh Research Fellow 2004-7
  • Winner of Corbett Prize at the International Conference on Defects in Semiconductors, 2001

Selected publications

G.Naresh-Kumar, B.Hourahine, P.R.Edwards, A.P.Day, A.Winkelmann, A.J.Wilkinson, P.J.Parbrook, G.England, C.Trager-Cowan, "Rapid nondestructive analysis of threading dislocations in wurtzite materials using the scanning electron microscope", Phys. Rev. Lett. 108, 135503 (2012) doi: 10.1103/PhysRevLett.108.135503

F.Papoff, B.Hourahine, "Geometrical Mie theory for resonances in nanoparticles of any shape", Opt. Exp. 19, 21432-21444 (2011) doi: 10.1364/OE.19.021432

K.Wang, K.P.O'Donnell, B.Hourahine, R.W.Martin, I.M.Watson, K.Lorenz, E.Alves, "Luminescence of Eu ions in AlxGa1-xN across the entire alloy composition range", Phys. Rev. B 80, 125206 (2009) doi: 10.1103/PhysRevB.80.125206

S.Sanna, B.Hourahine, U.Gerstmann, T.Frauenheim, "Efficient tight-binding approach for the study of strongly correlated systems", Phys. Rev. B 76, 155128 (2007) doi: 10.1103/PhysRevB.76.155128

B.Aradi, B.Hourahine, T.Frauenheim, "DFTB+, a sparse matrix-based implementation of the DFTB method", J. Phys. Chem. A 111, 5678-5684 (2007) doi: 10.1021/jp070186p

M.Hiller, E.V.Lavrov, J.Weber, B.Hourahine, R.Jones, P.R.Briddon, "Interstitial H-2 in germanium by Raman scattering and ab initio calculations", Phys. Rev. B 72, 153201 (2005) doi: 10.1103/PhysRevB.72.153201

S.Petit, R.Jones, M.J.Shaw, P.R.Briddon, B.Hourahine, T.Frauenheim, "Electronic behavior of rare-earth dopants in AlN: A density-functional study", Phys. Rev. B 72, 073205 (2005) doi: 10.1103/PhysRevB.72.073205

D.Prezzi, T.A.G.Eberlein, R.Jones, B.Hourahine, P.R.Briddon, S.Oberg, "Hydrogen-related photoluminescent centers in SiC", Phys. Rev. B 70, 205207 (2004) doi: 10.1103/PhysRevB.70.205207

B.Hourahine, R.Jones, "Infrared activity of hydrogen molecules trapped in Si", Phys. Rev. B 67, 121205 (2003) doi: 10.1103/PhysRevB.67.121205

O.Andersen, A.R.Peaker, L.Dobaczewski, K.B.Nielsen, B.Hourahine, R.Jones, P.R.Briddon, S.Oberg, "Electrical activity of carbon-hydrogen centers in Si", Phys. Rev. B 66, 235205 (2002) doi: 10.1103/PhysRevB.66.235205

M.I.Heggie, C.P.Ewels, N.Martsinovich, S.Scarle, R.Jones, J.P.Goss, B.Hourahine, P.R.Briddon, "Glide dislocations in diamond: first-principles calculations of similarities with and differences from silicon and the effects of hydrogen", J. Phys. Condens. Matter 14, 12689-12696 (2002) doi: 10.1088/0953-8984/14/48/304

J.P.Goss, B.Hourahine, R.Jones, M.I.Heggie, P.R.Briddon, "p-type surface doping of diamond: a first-principles study", J. Phys. Condens. Matter 13, 8973-8978 (2001) doi: 10.1088/0953-8984/13/40/313

Current Grants

Francesco Papoff, Benjamin Hourahine, , , ,
Royal Society (2012-2014) £12000
Title: Time resolved energy transfer and localization in nanophotonic structures

Carol Trager-Cowan, Benjamin Hourahine, Robert Martin, Kevin O'Donnell, ,
EU (2008-2012) £312014
Title: RAINBOW ITN (Marie Curie)