Articles

Prof. John Okumu

 

Deputy Vice Chancellor (Academics)
Department of Physics
P.O. Box 43844 , 00100 Nairobi
Kenyatta University
NAIROBI
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. or This email address is being protected from spambots. You need JavaScript enabled to view it. or This email address is being protected from spambots. You need JavaScript enabled to view it.

Current Research

My recent work has focused on sputter deposition technique to thin films of transition metal oxides. The main goal is to have a better understanding of novel materials for device development. This involves the characterization of materials for various applications through the study of optical and structural properties using optical spectroscopy and x-ray diffraction analysis. The study of these materials has immediate applications in optical data storage, hard coatings and mirrors, and coatings for smart windows.

I have also recently started a project on fabrication of nanoparticles especially by sputter deposition in transition metal oxides. We research on a method that can produce a broad plasmon resonance band which is suited for photochromic applications. We try to understand these properties using x-ray diffraction, transmission electron microscopy and optical spectroscopy. In this work we collaborate with the 1st Institute of Physics, RWTH-Aachen, Germany.

Publications

Internationally Refereed Journals

Conference Papers

  • J.M. Linturi, J. Okumu and C.S. Singh, paper presented in the 1st East African Regional Scientific conference of Pure and Applied sciences held at Kenyatta University, Nairobi , Kenya.
  • E Jobunga, J. Okumu and C.S. Singh, “Electron impact excitation of the lowest autoionizing state of potassium using distorted wave method. Presented in the XXVII international conference on Photonic, Electronic and Atomic collisions held in Belfast, Northern Ireland, UK on 27th July 2011.
  • J.O. Agumba, P.M. Karimi, J. Okumu, and W.K. Njoroge,“Design and fabrication of a simple four point probe for electrical characterization of thin films”,1st East African regional conference of Pure and Applied Sciences, 10th -14th August 2010, Kenyatta University, Nairobi-Kenya.
  • E.O. Jobunga, J. Okumu and C.S. Singh, “Electron Impact Excitation of the lowest autoionization states of sodium using distorted wave method” 1st East African regional conference of Pure and Applied Sciences, 10th -14th August 2010, Kenyatta University, Nairobi-Kenya
  • W.K. Njoroge, C.K. Wangati, and J. Okumu, “Influence of sputter power and Chamber pressure on the optical properties of tungsten thin films deposited by Magnetron sputtering”. Pro. International Conference on Solar Energy Materials, 13th- 15th October, 2009, Dar es Salaam, Tanzania.
  • J. Okumu, C. Dahmen, A.N. Sprafke M. Lysberg, G. von Plessen and M. Wuttig, “Multicolor Photochromism in Silver nanoparticles in TiO2 matrix”. Pro. International Conference on Solar Energy Materials, 13th-15th October, 2009, Dar es Salaam,Tanzania.
  • E.U.O. Mapesa, J.M. Odote and J. Okumu, “Optical properties of indium-tin-oxide thin films prepared in a non-reactive ambient. Proceedings of the Ninth College onThin Film Technology, July 24th to 4th August 2006, University of Dar es Salaam,Tanzania.
  • J. Okumu and M. Wuttig, Optical properties of TiO2 loaded with silver nanopartiles,World Conference on Physics and Sustainable Development (31st October-2nd November 2005), Durban, South Africa.
  • J. Okumu, C. Dahmen, A.N. Sprafke M. Lysberg, G. von Plessen and M. Wuttig, Photochromic silver in TiO2 matrix, 8th European Vacuum Congress Berlin 2003 (23rd -26th June 2003)-Berlin (Germany).
  • J. Okumu, C. Salinga, and W. Wuttig, Gasochromic Switching in MoOx Thin Films Deutschen Physikalischen Gesellschaft (German Physical Society) meeting-Dresden (24th -28th March 2003) Dresden (Germany).
  • J. Okumu, H. Weis, T. Petersen and M. Wuttig, '' Hydrogenation of Mg films for Optical Switches''. Pro. Regional workshop of Thin film Technology -Dar es Salaam (2000) p 52-56.
  • G.A. Ibitola J. Okumu and P.K. Karimi, ''High electron mobility Transistors: A review. Proc. 5th Regional Conference on Material Science and Device Technology. Nairobi (2000).
  • J. Okumu, "Theory of the band gap formation in amorphous silicon." Proc. Regional Conference on Developments in material science and Physics Education (Nairobi) (1996).

 

 

 

Last Updated on Friday, 11 March 2016 12:14

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