BrainMap

Mr. Ovidiu Cojocaru

PhD

Researcher - INSTITUTUL NAŢIONAL DE CERCETARE-DEZVOLTARE PENTRU FIZICA MATERIALELOR - INCDFM BUCUREŞTI

Researcher

I'm currently working at the National Institute of Materials Physics as Research Assistant in Lab. 70 - Group of Nanomaterials and Nanostructures based on Si-Ge-Sn. My experience - electrical and photoelectrical measurements; UV-Vis-NIR spectroscopy; ab initio computations for electronic structure properties of Si-Ge-Sn based nanocrystals and study of ferroelectric properties of high-k oxides (polarization)

Web of Science ResearcherID: A-4793-2019

Curriculum Vitae (15/03/2024)

Expertise & keywords

Multifunctional optoelectrical sensor based on two-dimensional MoS2 atomically thin layers grown by selective nucleation Call name: P 2 - SP 2.1 - Proiect experimental - demonstrativ
PN-III-P2-2.1-PED-2021-2457 2022 - 2024

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:

Project website: https://infim.ro/en/project/multifunctional-optoelectrical-sensor-based-on-two-dimensional-mos2-atomically-thin-layers-grown-by-selective-nucleation/

Abstract:

Optoelectrical multifunctional sensors will be obtained based on selective nucleation and growth of two-dimensional 2D-MoS2 atomically thin layers on SiO2/Si patterned substrates, by using Physical Vapor Deposition method. The substrate patterning will be performed by deposition of Mo pads before growth of MoS2 flakes. The precise localization of selectively grown 2D-MoS2 flakes allows the fabrication of the optoelectrical sensors by deposition of metallic contacts using photolithographic technique with alignment to the patterns of the substrate. The atomically thin 2D-MoS2 layers are very sensitive to external excitation as for example light illumination or adsorbed molecules on the 2D-MoS2 free layer surface. Using the Si substrate as gate electrode, the (photo)sensitivity of the device can be controlled and enhanced by field effect. Based on the high sensitivity expressed by electric and photoelectric behaviour, the 2D-MoS2 optoelectrical sensors are recommended for many practical applications, as for example biosensors (protein detection, DNA compatibility, acetone in human breath for diabetes, etc) and chemical sensors for pollution monitoring. The validation of the optoelectrical sensor demonstrator in this project according to TRL 3 includes the testing experiments on spectral photocurrent, as well as on electrostatic doping in 2D-MoS2 layers by field effect and adsorbed acetone molecules.

Synaptic neuron-like structure based on HfO2/GeSn with ferroelectric field effect that simulates a three-terminal memristor Call name: P 1 - SP 1.1 - Proiecte de cercetare pentru stimularea tinerelor echipe independente - TE-2021
PN-III-P1-1.1-TE-2021-1537 2022 - 2024

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:

Project website: https://infim.ro/en/project/synaptic-neuron-like-structure-based-on-hfo2-gesn-with-ferroelectric-field-effect-that-simulates-a-three-terminal-memristor/

Abstract:

This project propose the development of a synaptic structure based on HfOx/GexSn1-x with conductance modulated by ferroelectric field-effect. By improving the ferroelectric characteristics of HfOx using a high-mobility channel material (epi/poly GeSn) we obtain a synaptic neuron-like structure that simulate a three-terminal memristor for neuromorphic computing. The HfOx/GexSn1-x structure is obtained by reactive/non-reactive magnetron sputtering followed by Rapid Thermal Annealing in active working gas (H2/N2) to avoid the local disorder by passivating the dangling bonds and by healing the trap states. The remanent polarization will be enhanced for HfOx/GexSn1-x structure by controlling the interface between HfOx FeCAP and the GeSn high-mobility channel. The HfOx/GexSn1-x layers structure is morphological and structural characterized by XRD, XPS, HRTEM, and electrical measurements of the ferroelectric field-effect.

Photodetectors with GeSn nanocrystals in Si3N4 matrix highly photosensitive from 0.5 µm to 2.4 µm Call name: P 1 - SP 1.1 - Proiecte de cercetare pentru stimularea tinerelor echipe independente - TE-2021
PN-III-P1-1.1-TE-2021-1491 2022 - 2024

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:

Project website: https://infim.ro/en/project/photodetectors-with-gesn-nanocrystals-in-si3n4-matrix-highly-photosensitive-from-0-5-%c2%b5m-to-2-4-%c2%b5m/

Abstract:

The project goal is to fabricate a demonstrator for photodetector device with GeSn-nps (top contact/GeSn-nps:Si3N4/Si and/or quartz substrate/bottom contact), having targeted parameters: photocurrent to dark current ratio at least 2 orders of magnitude, fast photoresponse time:μs, spectral window extended toward 2.4 µm, high responsivity and good detectivity characteristics. We propose a new and original approach, by using an active layer that give an extended spectral limit in SWIR due to Si3N4 properties to induce a tensile strain in film. This consists in co-deposition or multilayer of different GeSn compozition and content in Si3N4. Objectives: O1: Fabrication by MS of the structure, GeSn-nps:Si3N4/ Si or quartz substrate, by using different novel approaches. For this, the critical deposition parameters (target power, work pressure, gas flux or substrate temperature) will be finely tuned to be optimized. O2: Formation of the GeSn-nps in Si3N4 matrix with controlled morphology (size, uniformity and density); O3: Developing the test samples with photoconductive properties controlled by morphology, completely characterized; O4: Obtaining the demonstrator of the photodetector device having targeted parameters, functionally tested according to TRL 3. Dissemination of the results: 1 patent, 3 ISI-quoted journals, 2 contributions to conferences and web page. The team expertise and facilities chosen to reach the project goal is a strong argument for the success of this project.

Multilayered floating gate nonvolatile memory device with GeSi nanocrystals nodes in nanocrystallized high k HfO2 for high efficiency data storage Call name: P 4 - Proiecte de Cercetare Exploratorie, 2020
PN-III-P4-ID-PCE-2020-1673 2021 - 2023

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:

Project website: https://infim.ro/en/project/multilayered-floating-gate-nonvolatile-memory-device-with-gesi-nanocrystals-nodes-in-nanocrystallized-high-k-hfo2-for-high-efficiency-data-storage-multigesincmem/

Abstract:

The project goal is to fabricate a multilayered floating gate (FG) nonvolatile memory device (ML NVM) with charge storage nodes of GeSi nanocrystals (NCs) embedded in nanocrystallized high k HfO2 matrix (capacitor of top contact/ gate HfO2/ n layers of GeSi NCs in HfO2 as FG/ tunnel HfO2/ Si wafer/ bottom contact, n=1 to 5 for the 5 versions NVM1-NVM5). We target in project to obtain high performance ML NVMs (memory window >4 V, charge loss ratio

Broadband photodetector based on hydrogenated GeSn layers. Call name: P 2 - SP 2.1 - Proiect experimental - demonstrativ
PN-III-P2-2.1-PED-2019-4468 2020 - 2022

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://infim.ro/en/project/broadband-photodetector-based-on-hydrogenated-gesn-layers/

Abstract:

The main goal of this project is the obtaining by magnetron sputtering (MS) deposition and hydrogenation of GexSn1-x:H alloy, a new photosensitive material for fabrication of high sensitive broadband photodetectors. By increasing the Sn concentration in GeSn alloy, the bandgap is narrowed and changed from indirect to direct bandgap semiconductor, making GeSn a good candidate for photodetectors with extended sensitivity to short-wave infrared range (SWIR). At international level, the hydrogenation of GexSn1-x to obtained amorphous and nanocrystalline GexSn1-x:H represents the novelty of the project proposal. The role of hydrogen in GexSn1-x:H alloy is to passivate the structural unintended defects, in order to increase the photosensitivity. This is similar to other semiconductors based on group IV of elements (a-Si:H and a-SiGe:H) intensively studied and reported in literature. Two different technological routes of obtaining GexSn1-x:H will be investigated: i) MS deposition of GexSn1-x films with various Sn content followed by hydrogen plasma treatment at different annealing temperatures; ii) direct deposition of GexSn1-x:H by reactive MS in atmosphere of hydrogen diluted in argon. In both cases, the nanocrystallization will be obtained by in-situ annealing during MS deposition or ex-situ by RTA treatment. For achieving the final goal that of obtaining a broadband photodetector with high sensitivity in SWIR, complex characterizations of GexSn1-x:H layers will be performed to find out the optimal technological parameters of the demonstrator. The demonstrator will be functionally tested in the lab according to TRL3. Such photodetectors with high sensitivity in SWIR are imperatively desired to replace the actual market devices based on toxic materials PbS and InGaAs. The results of the project activities may serve to future research on GexSn1-x:H for other practical applications as for example tandem a-SiGeSn:H solar cells.

Non-volatile memory based on ferroelectric HfO2 Call name: P 2 - SP 2.1 - Proiect experimental - demonstrativ
PN-III-P2-2.1-PED-2019-0205 2020 - 2022

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: https://infim.ro/en/project/non-volatile-memory-based-on-ferroelectric-hfo2-ferohafomemo/

Abstract:

The project scope is to fabricate a nonvolatile memory (NVM) demonstrator based on ferroelectric HfO2 with targeted parameters of 1.5–2 V memory window and good retention, starting from TRL 2 up to TRL 3. This device benefits from ferroelectric HfO2 advantages: low influence of parasitic charge trapping on NVM performance (high memory window of 1.5–2 V); CMOS compatibility; lateral and vertical gate-stack scaling; low power operation. The project objectives are: O1) magnetron sputtering deposition of NVMs in 3 versions (V1-V3) using 2 approaches of undoped and Ge-doped HfO2: V1) HfO2/Hf/HfO2/ Si (100), V2) (HfO2/Hf)n/ Si (100) with n = 1 and 2, V3) (HfO2/ZrO2)n/ Si (100); O2) Obtaining ferroelectric HfO2 or HfZrO phase in NVMs by post-deposition rapid thermal annealing (RTA) performed on versions V1-V3 and consolidation of ferroelectricity by post-metallization annealing (PMA); RTA and PMA represent new solution; O3) Obtaining good contacts (Pt, Al); O4) Developing test samples completely characterized (NVM properties, morphology, structure); O5) Fabrication of NVM demonstrator “metal contact/ferroelectric HfO2 or HfZrO/Si (100)/metal contact”; testing of functional parameters/characteristics at TRL 3. The project is beyond state of art and has high level of novelty as it proposes new solutions of new advanced materials and new technological approaches for NVM fabrication: *controlling density of O vacancies in HfO2 by controlling Ar/O2 ratio during deposition and by depositing Hf layer between/near HfO2 layers (V1, V2); *Ge doping of HfO2 and HfZrO (V1-V3); *tailoring layers thicknesses in V3. Results: i) scientific ones - 1 ISI paper and dissemination at prestigious international conferences in the field by 2 papers; ii) technological - 1 patent application. Experienced and postdoctoral researchers ensure the project accomplishment based on their high level expertise, and project team will gain new competences and EU and international visibility in NVMs field.

New advanced nanocomposites. Technological developments and applications Call name: P 1 - SP 1.2 - Proiecte complexe realizate in consorții CDI
PN-III-P1-1.2-PCCDI-2017-0871 2018 - 2021

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); INSTITUTUL NATIONAL DE CERCETARE-DEZVOLTARE PENTRU OPTOELECTRONICA INOE 2000 INCD (RO); UNIVERSITATEA DE VEST TIMISOARA (RO); ACADEMIA ROMANA FILIALA TIMISOARA (RO); UNIVERSITATEA BABES BOLYAI (RO); INSTITUTUL NATIONAL DE CERCETARE-DEZVOLTARE PENTRU FIZICA TEHNICA-IFT IASI (RO); INSTITUTUL NATIONAL DE CERCETARE DEZVOLTARE PENTRU FIZICA LASERILOR, PLASMEI SI RADIATIEI - INFLPR RA (RO); INSTITUTUL NATIONAL DE CERCETARE- DEZVOLTARE PENTRU MICROTEHNOLOGIE - IMT BUCURESTI INCD (RO); UNIVERSITATEA "DUNAREA DE JOS" (RO); UNIVERSITATEA TRANSILVANIA BRASOV (RO); Ministerul Apararii Nationale prin Centrul de Cercetare Stiintifica pentru Aparare CBRN si Ecologie (RO)

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

Project website: http://infim.ro/project/kuncser_noi_directii_de_dezvoltare_tehnologica_si_utilizare_nanocompozite_avansate_47pccdi_2018

Abstract:

The development of complex nanocomposite materials consisting of different matrices (polymer-like, oxides, intermetallics, liquids) functionalized by different nasnostructured additions (carbon allotropes, magnetic nanoparticles with different organizations, nanostructured semiconductors, etc.) is the aim of this project. The unique combinations of interacting nanophases offeres to the hybrid nanocomposite material new or enhanced proprieties of high interest for applications. In this context, according to the previous experience of the involved teams, the complex project (formed by 4 component projects) is focused on the development of new optimized nanocomposite systems to be included in experimental demonstrators or final products to be transferred to economical companies. The project will contribute both to an increased scientific visibility of the partners as well as to enhancing the institutional performances by the development of new technical and scientific capacities.

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