Multifunctional zinc oxide thin films

Project financed by the Romanian National Authority for Scientific Research, UEFISCDI

Number: PN-II-ID-PCE-2011-3-0566; Contract number: 196 / 05.10.2011

Principal investigator: Dr. Magdalena Nistor

Summary

The aim of the project is to explore and develop an original approach for the growth of new advanced multifunctional oxide thin films with physical properties which could give rise to potential applications. We aim to demonstrate that by a precise control of the nature and concentration of dopants, the oxygen deficiency and structural defect density it is possible to tune the physical properties of oxide thin films and to give them new functionalities.
From the point of view of exploratory research, a model system has to be studied in order to check this approach, thus indium tin oxide and indium oxide thin films will be studied as transparent conducting electrodes and multifunctional films. However, due to their high cost and limited supply there is an urgent need to develop alternative materials with similar or better properties, one of the best candidates being zinc oxide.
In order to enhance an existing physical property or to induce a new one, undoped and doped zinc oxide thin films will be grown with twofold strategy: being a transparent and conducting electrode for Si solar cells and a conversion layer for the solar spectrum by the «down-shifting» phenomenon related to the presence of rare earth ions in the oxide matrix. Another main aspect of the project is to investigate the structure and microstructure of undoped and doped oxide films and the correlation with their optical, electrical and magnetic properties, in order to obtain oxide thin films presenting active properties for applications in the fields of photovoltaic and spintronics.

Objectives

-Growth and characterization of doped oxide thin films for transparent conducting electrodes with new functionalities
-The investigation of the role of nature and concentration of dopants, oxygen deficiency and defect density on the physical properties of doped oxide thin films in order to obtain films with specific functionalities
-Dissemination of the results: publication in international scientific ISI journals, presentations in major international conferences in the field

Research Team

National Institute for Lasers, Plasma and Radiation Physics (NILPRP)
Department of Plasma Physics and Nuclear Fusion
Plasma Chemistry and Advanced Functional Materials Group

Magdalena Nistor, project leader, PhD, senior researcher
Florin Gherendi, PhD, senior researcher, member of the team
Nicolae Bogdan Mandache, PhD, senior researcher, member of the team
Stefan Radan, technician, member of the team

International Cooperation:
Dr. J. Perriere, within a French-Romanian scientific cooperation agreement between NILPRP and INSP, Université Pierre et Marie Curie, France
Prof. E. Millon, GREMI, Université d’Orleans,France
W. Seiler, PIMM, Arts et Métiers ParisTech, Paris, France

Results

Phase I (Oct. 2011 – Dec. 2011)

In the first stage of the project undoped and doped oxide thin films were grown by pulsed electron beam method (PED) in function of different growth parameters in order to optimize the film properties. Precise measurements of the composition, crystalline quality and surface morphology of these oxide thin films were performed.
Report

Phase II (Jan. 2012 – Dec. 2012)

In the second stage of the project undoped and doped oxide thin films were grown and characterized by means of Rutherford Backscattering Spectrometry (RBS), X-ray diffraction, Scanning Electron Microscopy, resistivity and Hall effect measurements at room temperature and/or in function of the temperature and optical measurements. The influence of the nature and concentration of dopants, oxygen deficiency and defect density on the physical properties of doped oxide thin films have been studied in order to obtain films with specific functionalities. The physical properties of doped zinc oxide films were compared to those of the model system, indium oxide thin films. Epitaxial oxide thin films have been grown with improved electrical and optical properties. The control of the oxygen incorporation in the oxide films induces very specific transport properties.
Report

Phase III (Jan. 2013 – Dec. 2013)

In the third stage of the project, oxide thin films with physical properties which could give rise to potential applications have been studied. Different oxide thin films have been grown and characterized by means of Rutherford Backscattering Spectrometry (RBS), X-ray diffraction, Scanning Electron Microscopy, electrical and optical measurements. The correlation between the composition and structure of undoped and doped oxide films and their electrical and optical properties has been studied in order to obtain oxide thin films presenting active properties for applications in the photovoltaic field. The study of metal-semiconductor transition in these films and their interpretation in the frame of the quantum corrections to conductivity in disordered oxides has been also performed. Transparent self-assembled source–channel–drain structures (i.e. multifunctional thin films) were grown in a single deposition with a resistivity variation of a few orders of magnitude between the channel region to source–drain region leading to the fabrication of transparent thin film transistors.
Report

Phase IV (Jan. 2014 – Dec. 2014)

In the fourth stage of the project the studies were focused on the growth and characterization of multifunctional zinc oxide thin films. Optical properties of zinc oxide thin films grown under different conditions were investigated and discussed. High optical transparency in the visible range was obtained for multifunctional zinc oxide thin films. Measurements of the photoluminescence properties of the doped ZnO thin films have been performed demonstrating their role as active converting layer. Due to the very anisotropic expansion dynamics of the plasma plume, non-uniformities in film thickness, stoichiometry, lattice parameter and the texture of zinc oxide films were evidenced as a function of position on the substrate, i.e. on the oblique incidence of the ablated species.
Report

Phase V (Jan. 2015 – Dec. 2015)

In the fifth stage of the project the studies on the growth and characterization of multifunctional zinc oxide thin films were continued. The properties of Nd-doped ZnO films were tuned by growth to have either metallic or semiconductor characteristics, with good optical transmittance in the visible range. Moreover, a low-temperature metal-insulator transition was observed in films grown under low oxygen pressure. Resistivities as low as 6 × 10−4 Ω cm and 90% optical transmittance in the visible range and different near infrared transmittance are obtained with approximately 1.0–1.5 at.% Nd doping and growth temperature of 500 °C.
Report

Phase VI (Jan. 2016 – Dec. 2016)

In the sixth stage of the project the studies were focused on the growth and characterization of multifunctional zinc oxide thin films. Nd-doped ZnO films with highly tunable properties were grown by pulsed electron beam deposition at different temperature on Si and c-cut single crystal substrates. In particularly, Nd-doped ZnO films have been obtained either as transparent semiconductor and photon energy converter or as highly conductor without energy conversion. Details about results obtained in this Phase can be found in following paper RSC Adv., 2016, 6, 41465 presented in the Dissemination section. In conclusion, the objectives of Phase VI were realized, resulting multifunctional zinc oxide thin films for applications.
Report

Conclusion (Oct. 2011 – Dec. 2016)

All the objectives of the project were realized.

Dissemination

Publications

  1. M. Nistor, F. Gherendi, N.B. Mandache, Appl. Surf. Sci. 258, 9274 (2012)
    http://dx.doi.org/10.1016/j.apsusc.2012.01.164
  2. E. Millon, M. Nistor, C. Hebert, Y. Davila and J. Perriere, J. Mater. Chem. 22, 12179 (2012)
    http://pubs.rsc.org/en/content/articlelanding/2012/JM/c2jm16753k
  3. M. Nistor, Rom.Rep.Phys. 64, 1313 (2012)
    http://www.rrp.infim.ro/2012supliment.html
  4. M. Nistor, J. Perrière, Solid State Communications 163 60 (2013)
    http://dx.doi.org/10.1016/j.ssc.2013.03.020
  5. W.Seiler, M.Nistor, C.Hebert, J.Perrière, Solar Energy Materials&Solar Cells 116, 34 (2013)
    http://dx.doi.org/10.1016/j.solmat.2013.04.002
  6. F.Gherendi, M.Nistor, S.Antohe, L.Ion, I.Enculescu and N. B. Mandache, Semicond. Sci. Technol. 28 085002 (2013)
    http://iopscience.iop.org/0268-1242/28/8/085002/
  7. F.Gherendi, M.Nistor,N.B.Mandache, J.Displ.Tech 9, 760 (2013)
    http://www.opticsinfobase.org/jdt/abstract.cfm?uri=jdt-9-9-760
  8. F.Gherendi, J.Optoel. Adv. M. 15 (No. 11-12), 1463 (2013)
    http://joam.inoe.ro/index.php?option=magazine&op=list&revid=81
  9. F.Gherendi, J.Optoel. Adv. M. 15 (No. 11-12), 1445 (2013)
    http://joam.inoe.ro/index.php?option=magazine&op=list&revid=81
  10. J. Perrière, C. Hebert, N. Jedrecy, W. Seiler, O. Zanellato, X. Portier, R. Perez-Casero, E. Millon, and M. Nistor, J. Appl. Phys. 116, 123502 (2014);
    http://scitation.aip.org/content/aip/journal/jap/116/12/10.1063/1.4896379
  11. M Nistor, W. Seiler, C. Hebert, E. Matei, J. Perriere, Appl.Surf.Sci. 307, 455 (2014).
    http://www.sciencedirect.com/science/article/pii/S0169433214008204
  12. M Nistor, E Millon, C Cachoncinlle, W Seiler, N Jedrecy, C Hebert and J Perrière, J. Phys. D: Appl. Phys. 48 195103 (2015) http://iopscience.iop.org/article/10.1088/0022-3727/48/19/195103
  13. M. Nistor, L. Mihut, E. Millon, C. Cachoncinlle, C. Hebert, J. J.Perrière, RSC Adv. 6, 41465-41472 (2016)
    http://pubs.rsc.org/en/content/articlelanding/2016/ra/c6ra07669f#!divAbstract

Conferences

Contact person

Dr. Magdalena Nistor, Senior researcher (CS I)
National Institute for Lasers, Plasma and Radiation Physics,
Department of Plasma Physics and Nuclear Fusion,
Plasma Chemistry and Advanced Functional Materials Group
Str. Atomistilor 409, 07725 Magurele-Bucharest, Romania
Tel / fax: +4021 4574490
E-mail: mnistor (at) infim.ro