The NFM research unit is one of the five departments of the ICMS. Each department carries out research in a different domain of materials science (catalysts, solid state reactions, functional nanomaterials and optical materials), sharing different facilities and some common services (e.g. administration, mechanical workshop) and instruments. Internally, each unit or department follows its own strategy and organization schemes. In particular, the NFM unit is mainly focused on the development of functional applications of materials in the form of thin films prepared with vacuum and plasma (V/P) methods. In addition, the development of pre-commercial devices to test these materials is an incipient activity of the unit.
For a better accomplishment of the scientific objectives, the NFM unit is organized in research lines (RLs) and in flexible and variable working groups which are adapted to the specific projects to be carried out. Each research line has a responsible investigator (RI) whose mission is to coordinate the use of the equipment and take care that these resources are properly used for the realization of the projects. Activities and distribution of resources within the RLs are coordinated by the scientific director who also acts as responsible for specially demanding projects.
Research lines of NFM unit
In the NFM unit, research activities are organized into three RLs which, being complementary in its objectives, cover most R+D aspects in the field of surface engineering by vacuum and plasma techniques:
- RL1.- Surface nanostructuration of materials by vacuum and plasma techniques.
- RL2.- Advanced characterization and properties of surface-functionalized materials.
- RL3.- Development of final applications and devices.
The definition of three research lines reflects the classical paradigm in Materials Science: synthesis-characterization-properties/applications. The RLs distribution in the NFM unit has been adapted to the vacuum and plasma technologies that constitute the core expertise of its activities. To favour the development of new applications, RL3 emphasizes the concept devices, while properties are considered together with advanced characterization techniques, as both aspects complement themselves.
The following chart gives a summarized description of the particular topics in which the unit is currently working.
NFM UNIT RESEARCH LINES
RL1.- SURFACE NANOSTRUCTURATION OF MATERIALS BY VACUUM AND PLASMA PROCESSES (V/P)
1.1. Simulation and modelling of thin film growth
1.2. Deposition of nanostructured thin films by PVD1 and PECVD2 methods
1.3. Growth of supported 1D nanostructures by VPP3
RL2.-ADVANCED CHARACTERIZATION AND PROPERTIES OF SURFACE FUNCTIONALIZED MATERIALS
2.1. Advanced characterization by electron microscopy
2.2. Photoemission and related techniques
2.3. Photonic properties of materials
2.4. Tribology of surface functionalized materials
2.5. Characterization of surfaces by scanning probe microscopes
RL3.-DEVELOPMENT OF FINAL APPLICATIONS AND DEVICES
3.1. Wetting and bioactive surfaces
3.2. Energy applications: photovoltaics
3.3. Energy applications: fuel cells, piezoelectric and hydrogen production and storage systems
3.4. Monitoring and sensing: Photonic sensors
3.5. Wetting, anti-icing and biomaterial surfaces.
3.6. Photocatalytic active surfaces
3.7. Coatings for aggressive and specific environments
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1 Physical Vapour Deposition
2 Plasma Enhanced Chemical Vapour Deposition
3 Vacuum Plasma Processes
Specific content of the research lines and themes
RL1 aims at achieving a precise control of the vacuum and plasma methodology to control a la carte the micro- and nano-structure of thin films, multilayers and supported 1D structures. Among the different applied methodologies we can quote the physical vapor deposition of thin films at glancing angles (1), the use of organic nanowires as sacrificial templates to grow oxide nanowires (2), nanotrees and other 1D and 3D supported nanostructures, the preparation of compact nanocomposite and multilayers for advanced resistance functions (3), etc. The intelligent control of the film microstructure is supported by numerical simulations and theoretical models of the deposition which, at the same time, serve to propose new methodologies and approaches to grow requested and under design nanostructured surfaces (4).
RL2 focuses on the characterization of nanostructured films and the determination of their properties. Thin film chemistry, crystalline structure and microstructure are characterized by a large variety of methods. To maximize their performance for functional applications, determination of specific properties is essential. The unit has a strong background in photonic, electrical, wetting, catalytic, bioactive and tribological properties (5-7). In some cases like in photonics, this requires a high expertise combining modelling and experimental analytical approaches. Some researchers are expert in the development of electron microscopy and photoemission techniques to the analysis of the synthesized nanostructures (8, 9). Their contribution to the advancement of these techniques can be taken as research themes on their own.
RL3 is highly application-oriented and, still in an incipient way, involves the fabrication of prototype devices. Control the wetting, anti-icing, tribology and bioactivity (10-13) of the nanostructred thin films and supported nanostructures constitute features requiring a strict control over chemical composition and surface microstructure. Films or nanostructures are also incorporated in devices and active responsive systems that react to the medium and externally applied stimulus. Specially designed films and nanostructures have been incorporated in photovoltaic cells (14), fuel cells (15) and electrochemical sensors (16), optofluidic photonic sensors (17), hydrogen storage systems (18) or piezoelectric devices (19). A derived activity of RL1 and RL3 relying on atmospheric plasmas which is not strictly within the field of material science is the plasma-catalysis synthesis of gases of industrial interest (e.g., hydrogen, ammonia, etc. (20, 21).
Working methodology of the unit
The philosophy underpinning this working scheme is as follows: a strong background in V/P DEPOSITION processes (i) is the basis for the development of specific methodologies for the NANOSTRUCTURATION AND GROWTH of thin films and 1D nanostructures (ii), which are subjected to a thorough CHARACTERIZATION and properties determination (iii) to select the best conditions and materials for the development of ADVANCED FUNCTIONAL APPLICATIONS (iv) and devices (v). In i) the NFM unit has succeed in the implementation and/or development of processing techniques such as PECVD, Remote plasma assisted deposition (RPAD, originally developed in the NFM unit (22)), PVD at glancing angles (e-beam and magnetron sputtering (23, 24)), DC, AC, pulsed and reactive magnetron sputtering (MS), High Power impulse Magnetron Sputtering (HIPIMS) (25) and an incipient activity in the laser treatment of surfaces (26). The systematic application of plasma diagnosis tools and other monitoring processes during the deposition has been a requisite for the successful development of these processing tools (27). In ii) the NFM unit has developed Monte Carlo simulation tools capable of describing and predicting the growth of thin films as a function of experimental constrains. Its use has enabled the preparation of singular sculptured thin films (5), supported 1D nano-objects (2) or self-organized nanostructures with outstanding properties for specific applications (28).
Singular properties for specific applications have been unraveled in iv) thanks to the use of advanced characterization tools determining the chemistry, nanostructure, crystalline structure and optical, electrical, wetting and tribological properties. In addition, NFM researchers have extraordinarily contributed to the development of techniques such as electron microscopy and photoemission. The scientists responsible for these two services in the ICMS belong to the NFM unit (Profs. J.P. Espinós and A. Fernández, respectively), while other members have significantly contributed to the development of these techniques (Drs. F. Yubero, A. Borras and C. Rojas) in collaboration with international leading groups (Prof. S. Tougaard from the Univ. Southern Denmark in XPS and Prof. P. A. Midgley from Univ. Cambridge in TEM). Two warrant researchers act as responsible scientists of the IR and Raman ICMS services (Drs. A. Barranco and J. C. Sánchez-López).
Distribution of personnel and management procedure
The RI of each RL is in charge of the organization of the activities of the different research projects, use of laboratories, scheduled the use of the instruments, sharing facilities, etc. The current RI persons for each RL are the following senior researchers:
- RL1.- Prof. José Cotrino Bautista.
- RL2.- Prof. Asunción Fernández Camacho.
- RL3.- Prof. Juan Pedro Espinós Manzorro
Usually, RI are those with more experience in the specific theme and can be substituted every four year or, upon their own request. The scientific director of the unit (prof. Agustín R. González-Elipe) coordinates all the NFM activities, mediates in case of conflicts, takes care of the unit web page, promotes the collaboration with other entities and, as is the case of the present applications, promotes common initiatives of the unit (for example CONSOLIDER projects, LANE laboratory). Formally, a researcher represents the unit into the governing board of the ICMS, general meetings of the staff personnel and general assemblies of all personnel. This representing delegate can be the scientific director or a delegated person elected by the staff members. At present, this person is Dr. Alberto Palmero, one of the warrant researchers of the unit.
Unit members regularly meet once every month or whenever any urgent issue requires a straight response. In general, decisions are taken by consensus regarding questions such as the use of space, support to acquire large instruments, sharing and usage of common facilities or the participation in research projects. In this regard, distribution of personnel within these research projects is done according to objectives and taken into account the needs and expertise required in each case.
Besides the involvement of part of researchers in specific research projects, all personnel participates in common projects where they share facilities and equipment and work together in more ambitious objectives that go from the synthesis and characterization of surface functionalities to the development of specific applications. For example, during the past five years, an intense collaborative work has been carried out in the CONSOLIDER project Surface Functionalization of materials for high added value applications (FUNCOAT, 2009-2014) and in its natural continuation in the network Surface functionalization of materials for advanced applications (FUNCOAT+, 2016-2018 ), together with sixteen other laboratories in Spain in the field of surface technologies. This common involvement has made possible the development of the ambitious EU infrastructure project ALNANOFUNC (Advanced Laboratory for the Nanoanalysis of Novel Functional Materials, UE CT-REGPOT-2011-1-285895, Coordinated by Prof. A. Fernández, 2011-2015, total budget above 2.6M) dedicated to bestow the unit and the ICMS with an up to date electron microscopy laboratory for the advanced characterization of nanomaterials. Similarly, several researchers from the unit have acted as PI the latest calls from MINECO regarding the acquisition of new instruments and facilities with a total investment higher than 570k.
The scientific personnel and engineers of the unit distribute within the three research lines in a supple way according to their own expertise and its adequacy to the RL topic. It may happen that a researcher participates in more than one research line. The distribution of scientific personnel and engineers within these research lines is as follows:
- RL1.- Agustin R. González-Elipe, José Cotrino, Asunción Fernández, Ana Borrás, Alberto Palmero, Rafael Alvarez, Ana Gómez-Ramirez, Victor Rico.
- RL2.- Agustin R. González-Elipe, Asunción Fernández, Juan P. Espinós, Francisco Yubero, Angel Barranco, Juan C. Sanchez-López, Cristina Rojas, Victor Rico, Maria C. Jiménez de Haro.
- RL3.- Agustin R. González-Elipe, Asunción Fernández, Juan P. Espinós, Francisco Yubero, Angel Barranco, Juan C. Sanchez-López, Aranzazu Díaz, Ana Borrás.
References
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24.-R. Alvarez et al., Plasma Proc. Polym. 12 (2015) 7
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