BrainMap

Mrs. Viorica Stancu

- INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA

Researcher

Web of Science ResearcherID: not public

Expertise & keywords

Optimized pyroelectric materials through the polarization gradient concept and experimental model for a pyroelectric detector with potential for applications in monitoring high power/energy lasers. Call name: Joint Applied Research Projects - PCCA 2013 - call
PN-II-PT-PCCA-2013-4-0470 2014 - 2017

Role in this project:

Coordinating institution: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA

Project partners: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO); UNIVERSITATEA POLITEHNICA DIN BUCURESTI (RO); INTERNET S.R.L. (RO)

Affiliation: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO)

Project website: http://www.infim.ro/projects/optimized-pyroelectric-materials-through-polarization-gradient-concept-and-experimental

Abstract:

The project aims to develop materials with optimized pyroelectric properties using the polarization gradient concept and develop integral pyroelectric detectors for the near infrared (700 nm) to THz (≤100 µm) wavelengths range. These detectors have potential application also in the detection of high power or high energy laser beams (e.g. the lasers of ELI-NP project). The materials to be used in this project are ferroelectrics with a perovskite structure such as Pb(Zr,Ti)O3 (PZT) or (Ba,Sr)TiO3 (BST) due to the fact that the transition temperatures can be modified by changing the Zr or Sr content. These materials will be combined in structures of multilayers with gradient in concentration and polarization in order to increase the figure of merit M given by the ratio between the pyroelectric coefficient p and the dielectric constant ε (M=p/ε).

The present project proposes a novel way of increasing the merit figure M by increasing the pyroelectric coefficient. This can be achieved by developing materials that exhibit a concentration gradient in the direction of the polarization, which introduces a succession of phase transitions at different temperatures, leading to a more abrupt variation of the polarization with the temperature and thus to a larger pyroelectric coefficient.

Another effect to turn to account is the temperature variation of the dielectric constant which can contribute to further increase the total pyroelectric coefficient. The temperature variation of ε can contribute to the pyroelectric signal if an electric field is applied to the ferroelectric material in order to maintain a stable polarization state, thus averting possible signal variations caused by the ambient temperature conditions.

The materials with gradient in concentration and polarization will be realized in bulk form, as ceramic wafers (25 mm minimum diameter and 6 mm thickness) by using the spark plasma sintering (SPS). Alternately, the ceramic technology coupled with classical sintering, or hot press, can be used. The sintering conditions will be optimized in order to obtain the best p/ε ratio. The selected material will then be used to build the active elements for the pyroelectric detection. In this respect, metallic electrodes will be deposited and one of them will be blackened in order to ensure a better absorbtion of the incident electromagnetic radiation. A novel approach is that carbon nanotubes are to be used for the blackening. This way the absorbtion coeficient can be increased close to 1. The active element will then be used to create pyroelectric detectors, including the electronics for signal processing and the sofware needed for PC display. Beside the mentioned ceramic materials, epitaxial multilayered structures with gradient in concentration and polarization will be realized and their pyroelectric detection properties will be investigated as well during the project.

The consortium is formed by 3 partners: coordinator of the project –CO is a national institute with experience in ceramic materials and pyroelectric detection; one university –P1 with experience in preparation of ceramic powders; one company –P2 specialized in signal procesing and different types of electrical measurements. CO and P1 will develop the active element for the pyroelectric detection and P2 will develop and test the experimental model of the system for pyroelectric detection including all the electronics and the sofware needed for the different types of applications for which the pyroelectric detector is developed by CO and P2: automatizations, non-contact measurements of temperature or monitoring of the high power/energy laser beams. The ultimate goals are to obtain: a technological process for obtaining the active element of pyroelectric detection, as well as two experimental models, one for the Pyroelectric Detector and one for a Pyroelectric Detection System used to detect high intensity laser beams.

Metal-ferroelectric interfaces: From first principles to experimental optimization Call name: Projects for Young Research Teams - TE-2012 call
PN-II-RU-TE-2012-3-0320 2013 - 2016

Role in this project:

Coordinating institution: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA

Project partners: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO)

Affiliation: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO)

Project website: http://www.infim.ro/projects/metal-ferroelectric-interfaces-first-principles-experimental-optimization

Abstract:

Study of the PZT/metal interfaces using ab-initio and experimental investigations. The electronic properties of the SRO/PZT/metal samples will be investigated using a variety of methods ranging from C-V, P-V, I-V characteristics as well structural investigations. The experimental measurements will be used in conjunction with the numerical simulations in order to explain the drastic changes in the electronic properties of the MFM devices when then metal electrode is changed. The purpose of the investigations is to optimize the properties of the MFM structure for attractive memory applications.

Investigations on advanced dielectric materials and structures in Terahertz and millimeter waves Call name: Exploratory Research Projects - PCE-2012 call
PN-II-ID-PCE-2012-4-0654 2013 - 2016

Role in this project:

Coordinating institution: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA

Project partners: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO)

Affiliation: INSTITUTUL NATIONAL DE CERCETARE - DEZVOLTARE PENTRU FIZICA MATERIALELOR BUCURESTI RA (RO)

Project website: http://www.infim.ro/node/4190

Abstract:

At the present, terahertz technology is certainly one of the most dynamic research fields with wide variety of applications: terabit wireless communication, spectroscopy, biology, medical sciences, food control, security systems, etc. The project aims to investigate advanced conventional as well as structured materials in Terahertz and millimeter wave range. On one hand, highly accurate characterization methods of complex perovskite dielectrics (bulk and thin films) with high values of the product between the quality factor and the frequency will be developed for millimeter wave and Terahertz range. The application of development methods to measure ferroelectric perovskites in Terahertz range is very important for such applications as tunable photonic crystal filters. On the other hand, numerical and experimental investigations on structured materials will allow the study of the Terahertz spoof surface plasmon-polaritons in new complex geometries. The electromagnetic simulation, fabrication and characterization of the proposed materials and structures will benefit of recent acquisitioned state-of-the-art equipment in the host institution. The final outcome of the project will consist in solution for an improved controlled of the electromagnetic radiation in millimeter wave and Terahertz range.

Effect of interfaces on charge transport in ferroic/multiferroic heterostructures Call name: Complex Exploratory Research Projects - PCCE-2011 call
PN-II-ID-PCCE-2011-2-0006 2012 - 2016

Role in this project:

Coordinating institution: National Institute of Materials Physics

Project partners: National Institute of Materials Physics (RO); National Institute of Materials Physics (RO); National Institute of Materials Physics (RO); National Institute of Materials Physics (RO); National Institute of Materials Physics (RO); Alexandru Ioan Cuza University (RO)

Affiliation: National Institute of Materials Physics (RO)

Project website: http://www.infim.ro/projects/effect-interfaces-charge-transport-ferroelectricmultiferroic-heterostructures

Abstract:

The main objective of the project is to perform a detailed study of interfaces and their effect on the charge transport properties in a number of well defined artificial multiferroic structures. Charge transport is beneficial in some cases, for example in tunnel junctions, but can be detrimental in other cases, as for example devices based on magnetoelectric effect or in capacitor like structures. In all cases, at least the interfaces with the metallic electrodes are involved in charge transport, but other interfaces can be also involved if multilayer structures are used. The study will be performed on thin films and/or nanostructures, therefore a significant influence of interfaces on the electronic and ionic charge transport is expected. The start will be from simple capacitor-like structures, to elucidate the problem of electrode interfaces in the case of various ferroic oxides. Further on charge transport in relation with interfaces will be studied in mode complex, multilayer structures with possible applications in tunel junctions, diodes or field effect devices.

The project involves 6 research teams from 2 host institutions, one of which is the National Institute of Materials Physics from Bucharest-Magurele, and the other one is the Alexandru Ioan Cuza University (UAIC) from Iassy. The composition of the teams is a mixes experienced researchers with excellent track records regarding preparation, characterization and modelling of advanced multifunctional materials including oxides, and young scientists at the beginning of their carriers. Some 12 PhD thesis are expected to start during the project. The project is expected to have a major impact not only at the basic science level, reflected by publications in high ranking journals, but also at the level of applied research, as for example manipulation of charge transport through designing specific interfaces or developement of new oxide architectures for ferroelectric field effect controlled of spin currents.

Study of Induced Effects by Defects and Impurities on Optical, Electrical and Electronic Properties of Wide Band Gap Semiconductors Call name: Projects for Young Research Teams - TE-2011 call
PN-II-RU-TE-2011-3-0016 2011 - 2014

Role in this project:

Coordinating institution: Institutul National de Cercetare-Dezvoltare pentru Fizica Materialelor

Project partners: Institutul National de Cercetare-Dezvoltare pentru Fizica Materialelor (RO)

Affiliation:

Project website: http://www.infim.ro/projects/study-induced-effects-defects-and-impurities-optical-electrical-and-electronic-properties

Abstract:

The aim of this project is the analysis of wide band gap semiconductor (WBS) thin films by use of non-destructive characterization techniques: ellipsometry, XRD and luminescence. These materials have existing or potential applications in optics and/or electronics. WBS thin films will be obtained by use of different thin films growth methods: pulsed laser deposition, magnetron sputtering, sol-gel and direct growth from colloidal suspension. The influence of defects and impurities on optical, electrical and electronic properties of such materials will be analyzed. The results from presented optical studies will be verified by conventional electrical measurements and structural analysis by electronic microscopy.

The project is focused on 3 types of wide band gap semiconductors: zinc oxide (ZnO) pure or doped with different elements; zinc nitride (Zn3N2) and the intermediary phases during controlled oxidation; and aluminum indium nitride (AlxIn1-xN) pure and doped with Zn. One objective is to grow and to characterize the n-type semiconductors with reproducible properties.

The estimated results will bring new insights regarding the physics phenomena involved in the growth process and the material properties, essential for obtaining viable results. In addition, special activities will be included in the project concerning the correlation between the fundamental knowledge and practical necessities of electronics, and the standardization of the growth of thin films below 200C.

FILE DESCRIPTION	DOCUMENT
List of research grants as project coordinator or partner team leader
Significant R&D projects for enterprises, as project manager
R&D activities in enterprises
Peer-review activity for international programs/projects