Ge nanocrystals embedded in amorphous matrices with photoconductive properties


Project Director: Dr. Ionel STAVARACHE
Contract ID: cod PN-II-RU-PD-2011-3-0094
Project Director: Dr. Ionel Stavarache
Project Type: National
Project Program: Program 1 - Development of the national CD system;
Funded by: Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii - UEFISCDI
Contractor: National Institute of Materials Physics (NIMP)
Contract no.: PD33/05.10.2011
Status: Closed
Data de inceput: 05 Nov. 2011
Data finalizarii: 04 OCt. 2013

Project Summary:

Few studies in the literature focused on the (photo)electrical properties of nanocrystalline germanium (nc-Ge) based materials, in contrast with the structural and optical ones. The aim is to prepare and to study nanostructured films consisting of nc-Ge immersed in amorphous matrix with good photoconductive properties. To achieve this goal we propose the following objectives: 1 Preparation of films with different concentrations of nc-Ge embedded in amorphous matrices; 2 Study of electrical properties in correlation with the morphology of layers. Experiment and modelling; 3 Study of photoconductive properties in correlation with morphology of layers. Experiment and modelling; 4 Dissemination of research results. The intended original results are: optimal preparation conditions will be determined to obtain films with improved photoconductive properties; dominant electrical transport mechanism will be proposed and percolation parameters will be calculated; transitions between energy levels evidenced in electrical and photransport phenomena will be identified and corresponding quantum confinement energy levels will be found; films with improved photoconductive properties will be obtained. The dissemination will be made by:
3 scientific reports; 5 articles published in ISI-quoted journals; 3 contributions to prestigious international conferences; project Web page. The aim and objectives frame themselves in the Human Resources programme, Postdoctoral research projects subprogram.

Project leader: Dr. Ionel Stavarache

Postdoctoral advisor: Dr. Magdalena Lidia Ciurea

  1. „Dense Ge nanocrystal layers embedded in oxide obtained by controlling the diffusioncrystallization process”, A. M. Lepadatu, T. Stoica, I. Stavarache, V. S. Teodorescu, D. Buca, M. L. Ciurea, Journal of Nanoparticle Research 15:1981, 2013 (DOI: 10.1007/s11051-013-1981-y).
  2. „Annealing temperature effect on structure and electrical properties of films formed of Ge nanoparticles in SiO2”, I. Stavarache, A. M. Lepadatu, T. Stoica, M. L. Ciurea, Applied Surface Science (DOI: 10.1016/j.apsusc.2013.08.031, http://dx.doi.org/10.1016/j.apsusc.2013.08.031).
  3. „Electrical properties related to the structure of GeSi nanostructured films”, Ionel Stavarache, Ana-Maria Lepadatu, Iuliana Pasuk, Valentin Serban Teodorescu, and Magdalena Lidia Ciurea, trimis spre publicare la Physica Status Solidi B: Basic Solid State Physics.
  4. „Annealing induced changes in the structure, optical and electrical properties of Ge-TiO2 nanostructured films”, Ionel Stavarache, Ana-Maria Lepadatu, Valentin Serban Teodorescu, Aurelian Catalin Galca, Magdalena Lidia Ciurea, trimis spre publicare la Nanoscale Research Letter;
  5. ”Transmission electron microscopy study of Ge nanoparticles formed by annealing in hydrogen at 500 °C of GeSiO films”, Valentin Serban Teodorescu, Adrian Valentin Maraloiu, Ionel Stavarache, Ana-Maria Lepadatu, Magdalena Lidia Ciurea,  trimis spre publicare la Digest Journal of Nanomaterials and Biostructures.
  6. “Electrical behaviour related to structure of nanostructured GeSi films annealed at 700 oC”, Ana-Maria Lepadatu, Stavarache Ionel, Adrian Maraloiu, Palade Catalin, Teodorescu Valentin Serban, Ciurea Lidia Magdalena, International Semiconductor Conference, publicata in Proceedings vol.1, p. 109-112, CAS 2012, IEEE event, 15 – 17 octombrie, Sinaia.
  7. “Transport mechanisms in SiO2 films with embedded germanium nanoparticles”, Catalin Palade, Ana-Maria Lepadatu, Ionel Stavarache, Adrian V. Maraloiu, Valentin S. Teodorescu, Magdalena Lidia Ciurea, International Semiconductor Conference, publicata in Proceedings vol.1, p. 91-94, CAS 2012, IEEE event, 15 – 17 octombrie, Sinaia
  8. „Conduction mechanism versus annealing in SiO2 films with Ge nanoparticles”, C. Palade, A.M. Lepadatu, I. Stavarache, V.S. Teodorescu and M.L. Ciurea, 36th  Edition of  International Semiconductor Conference (CAS), publicata in Proceedings vol.1, p. 31-34, CAS 2013, IEEE event,  14-16 October, Sinaia, Romania, 2013.
  9. „Electrical behaviour of ge nanoparticles network embedded in SiO2 matrix”, Ionel Stavarache, Ana-Maria Lepadatu, Adrian V. Maraloiu, Catalin Palade, Valentin S. Teodorescu, and Magdalena Lidia Ciurea, E-MRS 2012 Spring Meeting, May 14 - 18 , Strasbourg, France 2012.
  10. „Electrical properties related to the structure of films with Ge nanoparticles embedded in SiO2 matrix”, Magdalena Lidia Ciurea, Ana-Maria Lepadatu, Ionel Stavarache, Catalin Palade, Valentin S. Teodorescu, (prezentata oral) EMRS 2012 Fall Meeting, 17 – 21 septembrie 2012, Varsovia, Polonia.
  11. “Structure and electrical characterization of GeSi nanostructured films”, Ana-Maria Lepadatu, Ionel Stavarache, Adrian Valentin Maraloiu, Catalin Palade, Valentin Serban Teodorescu, Magdalena Lidia Ciurea, EMRS 2012 Fall Meeting, 17 – 21 septembrie 2012, Varsovia, Polonia.
  12. „Electrical and structural properties of nanostructured GeSi films”, A.-M. Lepadatu, I. Stavarache, A. Maraloiu, C. Palade, V. S. Teodorescu, L. M. Ciurea, 3rd International Colloquium “Physics of Materials” (PM–3), 15 – 16 noiembrie 2012, Bucuresti.
  13. „Electrical behaviour related to the structure of SiO2 films with embedded Ge nanoparticles”, I. Stavarache, C. Palade, A. M. Lepadatu, A. V. Maraloiu, V. S. Teodorescu, M. L. Ciurea, 3rd International Colloquium “Physics of Materials” (PM–3), 15 – 16 noiembrie 2012, Bucuresti
  14. „Influence of annealing on Raman and electrical properties of Ge nanocrystals in amorphous SiO2”, I. Stavarache, A.M. Lepadatu, A. V. Maraloiu, C. Palade, V. S. Teodorescu, and M. L. Ciurea, E-MRS 2013 Spring Meeting, May 27 - 31, Strasbourg, France 2013.
  15. „Study of Ge nanocrystals formation in Ge/SiO2 multilayer structures by TEM and Raman spectroscopy”, A.M. Lepadatu, I. Stavarache, V. S. Teodorescu, T. Stoica, M. L. Ciurea,EMRS 2013 Spring Meeting, 27 – 31, Stasbourg, France 2013.
  16. „Raman and electrical properties of Ge-SiO2 films versus annealing temperature”, A.M. Lepadatu, I. Stavarache, T. Stoica and M. L. Ciurea,The 6-th Edition of the Conference on Amorphous and Nanostructured Chalcogenides (ANC-6), Brasov (Romania), June 24-28, 2013.

Dr. Ionel Stavarache

405A Atomistilor Street, PO BOX MG-7, 077125

Magurele, ILFOV

email: stavarache@infim.ro

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