Nanomaterials Growth Division

Division Leader: José Santiso

Overview

  • Epitaxial thin-film deposition and characterisation of different materials, mainly perovskite structure related oxides. Interplay between strain and relaxation mechanisms, microstructure and functional properties of ultrathin films. Particular emphasis is given to the advanced TEM characterisation of defects at the nanoscale, such as misfit dislocations at the interface and their role in generating new functionalities
  • Current research is mainly devoted to the thin epitaxial growth of mixed ionic-electronic conducting oxides and multilayers by PLD, their structural characterisation by RHEED and XRD, and high-temperature electronic transport properties. Oxide and protonic ionic conductivity in thin films
  • Fundamental aspects of interfacial phenomena in the electrical characterisation of thin films of layered oxide materials and multilayers for use as components in intermediate temperature SOFCs
  • Surface composition segregation and its effect on oxygen surface exchange kinetics and ageing phenomena
  • MOCVD growth of 2D layers of transition metal dichalcogenides

In 2016 the Nanomaterials Growth Division continued working on the following closely-related main research objectives:

Thin-film deposition of epitaxial oxide materials by means of a pulsed laser deposition technique. Our division produces films for and in close collaboration with a large number of the ICN2 research groups. In some cases the thin-film deposition requires the use of reflection high-energy electron diffraction (RHEED). Our division carries out the preliminary structure characterisation, for the most part by X-ray diffraction. (Some of the ICN2 group leaders we collaborate with are: G. Catalan, J. Fraxedas, S. Valenzuela, C. Torres, and J. Nogués)

Investigation of the interplay between strain relaxation phenomena and functional properties in complex oxide films. This involves the development of novel methods for the X-ray diffraction and diffuse scattering characterisation of microstructure features in epitaxial thin films. These include in-plane diffraction, GISAXS analysis, as well as 3D reciprocal space mapping, the latter of which requires the use of synchrotron radiation source (i.e. BM25-ESRF and KMC2-Bessy). Most of the work is carried out in collaboration with Institut de Ciència de Materials de Barcelona (ICMAB). The microstructure research is completed via HRTEM characterisation.

Study of fundamental aspects of ionic and electronic charge and mass transport in the electrical characterisation of thin films of layered oxide materials and multilayers, for their use as components in intermediate temperature SOFCs. We are particularly interested in surface and interfacial oxygen exchange phenomena in order to obtain enhanced oxygen transport performance. Development of novel characterisation tools of the oxygen surface exchange kinetics. For this purpose we have developed a novel technique that uses the subtle chemical expansion measured by X-ray diffraction produced in transition metal oxide thin films when changing their oxygen stoichiometry to in-situ probe their redox kinetics at high temperature in time intervals as short as a few seconds. The setup also allows for electrical contacts which may be used either to simultaneously measure electrical conductivity relaxation or to apply an electric field for in-operando device electrochemical characterisation. 

Investigation of the surface activity for oxygen reduction in transition metal oxide perovskite thin films. Development of novel methods for determining oxygen surface exchange rate by combining electric conductivity relaxation and time-resolved X-ray diffraction experiments. We explore surface cation composition segregation mechanisms affecting the reactivity of the surfaces. This work is mostly carried out in collaboration with different international partners (Imperial College London, I²CNER at Kyushu University and MIT).

This year we built a new thin film MOCVD reactor for the growth of high quality ultrathin transition metal dichalcogenides, starting with MoS2, in collaboration with the ICN2 group led by Prof. José Antonio Garrido. We are currently working on a further scaling-up of this reactor to deposit films in 2” wafers.

Division Leader

José Santiso

CSIC Tenured Scientist

Dr. José Santiso earned his degree in Physics at the Universitat Autònoma de Barcelona (UAB) in 1988, later obtaining his PhD from the University of Barcelona (UB) in 1993. After his doctoral studies, he worked as a visiting scientist at Cambridge University (UK) from 1994 to 1996.

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