Professor P. O'Brien

Telephone:0171-594-5825

FAX: 0171-594-5804 Telex: 929484 IMPCOLG

e-mail pobrien@ic.ac.uk

 

An Overview of Recent work in My Group (Barton Lab)

Materials Synthesis: II/VI, III/VI and III/V semiconductors and oxides.

  1. Thin Films by MOCVD: Metal Organic Chemical Vapour Deposition
  2. Conventional MOCVD:- Improved handling of metal alkyls by the use of adducts: control of mass transport, control of reactivity use as dopants control of flow rate.
  3. Single Precursor Approaches:- The use of thiols, selenols, thio or seleno-carbamates, novel materials from novel precursors factors controlling deposition, InS, CdS etc.
  4. Nanodispersed Materials:- Especially Cd or Zn chalcogenides, surface derivatised sub-micrometric and nano-metricmaterials, especially as prepared from simple single molecule precursors.
  5. Chemical Bath Deposition:-The preparation of thin films, or dispersed materials by controlled chemical reaction in aqueous solution e.g. CdS from thiourea containing solutions with metal-ion buffered cadmium. The importance of supersaturation.

Coordination and Bioinorganic Chemistry: Speciation and Toxicity:-

  1. Cadmium Toxicity:- The effect ofcadmium on toxicity to mammalian cells in culture, quantification usingspeciation calculations.
  2. Cadmium Complexes Nmr and solid state nmr studies.
  3. Cadmium and Clays The effect of solution speciation on the nature of the species sorbed, preliminary observations.
  4. Carbamates The unusual properties of amino acids with low values for the pKa at nitrogen and possible affects on neurotoxicity.
  5. Chromate Toxicity DNA lesions toxicity and the importance of reduction mechanisms.

Selected Recent Publications

See Book cover Above.

1. Precursor chemistry: remaining challenges and some novel approaches, P. O’Brien, M. A. Malik, M. Chunggaze, T. Trindade and J. R. Walsh and A. C. Jones, J. Cryst. Growth, 1996, 170, 23.

2. Precursors for electronic materials, P. O'Brien in "Inorganic Materials" 2nd (revised) ed. D. Bruce and D. O'Hare, John Wiley, London and New York, 1996, 523.

3. Contrast Media ( Feature Article), C. Bartram, B. Laermann and P. O’Brien, Synergy, Dec 1996, 34.

4. The synthesis of CdS and CdSe nanocrystallites using a novel single molecule precursor approach, T. Trindade and P. O’Brien, Chem. Mater., 1997, 9, 523.

5. Lead dithiocarbamato complexes as precursors for the LP-MOCVD of lead sulfide, P. O’Brien and T. Trindade, Adv. Mat. Chem. Vap. Dep., 1997, 3, 75.

6. An unusual coordination mode in a bis(dialkyldithiocarbamato)-zinc(II) adduct with N,N,N’,N’-tetramethylethylenediamine: the X-ray crystal structures of ([MeiPrNCS2]2Zn)2Me2N(CH2)2NMe2  and [MeiPrNCS2]2ZnC5H5N, M.A. Malik, M. Motevalli, P. O’Brien and J.R. Walsh, Inorg. Chem., 1997, 36, 1263.

7. A study of the kinetics of the reduction of chromate by ascorbate under aerobic and anaerobic conditions, P. O'Brien and N. Woodbridge, Polyhedron, 1997, 16, 2081.

8. The use of an adduct in improved synthesis of nano-particulate chalcogenide semiconductors containing cadmium, M. Green and P. O'Brien, Adv. Mater.Opt. Elect., 1997, 7, 277.
 
9. The properties of some volatile alkyl(dialkylamido)zinc(II) and bis(dialkylamido)zinc(ii) compounds: potential zinc precursors in MOCVD, M. A. Malik and P. O’Brien, Polyhedron, 1997, 16, 3593.

10. Synthesis of PbS nanocrystals using a novel single molecule precursor approach: X-ray single crystal structure of  Pb(S2CNEtPri)2, T. Trindade, P. O’Brien, Xiao-mei Zhang and and M. Motevalli, J. Mater. Chem., 1997, 7, 1011.
 
11. The growth of indium selenide thin films from a novel asymmetric dialkyldiselenocarbamate of indium, P. O’Brien, D. J. Otway and J. R. Walsh, Adv. Mater., Chem. Vap. Dep., 1997, 3, 227.

12. Atomic layer epitaxy of GaAs using trisneopentyl gallium, P. Yeo, R. Sares, S. P. Watkins, G. A. Horley, P. O’Brien and A. C. Jones, J. Elect. Mater.,, 1997, 26, 1174.

13. The X-Ray single crystal structure of a gallium citrate complex, H. Salacinski and P. O’Brien, J. Amer. Chem.Soc., 1997, 119, 12695.

14. Growth mechanisms in the atomic layer epitaxy of GaAs, P. Yeo, R. Ares, S. P. Watkins, G. A. Horley, P. O’Brien and A. C. Jones, J. Appl. Phys., 1998, 83, 3390.

15. The deposition of thin films of CdSe or ZnSe by MOCVD using simple air-stable precursors, M. Chunggaze, P. O’Brien  J. McAleese and D. J. Otway, J. Chem. Soc., Chem Commum., 1998, 833.

16. MOCVD of zirconia thin films by direct liquid injection using a new class of zirconium precursor, A. C. Jones, T. J. Leedham, P. J. Wright, M. J. Crosbie, P. A. Lane, D. J. Williams, K. A. Fleeting, D. J. Otway and P. O’Brien, Adv. Mater., Chem. Vap. Dep., 1998, 4, 46.

17. A novel simple process for the deposition of thin films of CuInSe2 by MOCVD, P.O’Brien  J.McAleese and D.J.Otway, Adv. Mater., Chem. Vap. Dep, 1998, 4, 94.

18. Some novel carbamato chemistry of cadmium and zinc, M. A. Malik and P. O’Brien, Inorg. Chim. Acta, 1998, 24, 239.

19. A novel synthesis of cadmium phosphide nanoparticles using the single source precursor [MeCdPtBu2]3, P. O’Brien and M. Green, Adv. Mater., 1998, 10, 527.