Category Archives: Science of Graphene and Related 2D Structures

Priopcenje za javnost povodom opstruiranja financiranja iz EU fondova od strane MZOS-a

  Wednesday June 8th, 2016 , , ,

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PRIOPĆENJE ZA JAVNOST – Zagreb, 7. lipnja 2016.

Otvoreno pismo ministru znanosti, obrazovanja i sporta Predragu Šustaru:

‘‘Opstruiranjem financiranja iz EU fondova hrvatskih znanstvenih centara izvrsnosti ugrožava se 50 milijuna eura iz strukturnih fondova i radna mjesta za hrvatske znanstvenike – traži se hitna reakcija ministra Šustara!‘‘

Pedeset milijuna eura, upitna radna mjesta za čak tri stotine doktoranada i postdoktoranada, te riskiranje penala od Europske komisije, samo su dio crne statistike koja ozbiljno prijeti Republici Hrvatskoj (RH), a odvija se u sjeni problema s kurikularnom reformom.

Deset znanstvenih centara izvrsnosti proglašenih od strane Ministarstva znanosti obrazovanje i sporta (MZOS) tijekom 2014. i 2015. godine na prijedlog Nacionalnog vijeća za znanost, visoko obrazovanje i tehnološki razvoj, posljednjih su nekoliko mjeseci postalo taocem MZOS-a.

Naime, RH se strateški odredila kroz Operativni program (OP) za financiranje Znanstvenih centara izvrsnosti (2014 – 2020), te se prema Operativnom programu očekuje 50 milijuna eura iz Europskog fonda za regionalni razvoj (ERDF) koji bi bili na raspolaganju proglašenim centrima.

Kako bi centri mogli iskoristiti europska sredstva, MZOS je obvezan raspisati natječaj. Prvi indikativni rok za raspisivanje natječaja bio je 31. ožujka, te je pomaknut na 1. lipnja 2016., a natječaj još nije raspisan.

Unatoč brojnim službenim molbama za poštivanjem obveza koje su voditelji Znanstvenih centara izvrsnosti posljednjih mjeseci dostavili ministru Šustaru i premijeru Oreškoviću s upozorenjem da je RH preuzela obvezu te je dužna raspisati planirani natječaj iz strukturnih fondova u sklopu kojih bi se izvršila evaluacija planiranih troškova u okviru pojedinih centara, s današnjim datumom MZOS još uvijek nije aktivirao natječaj Europskog fonda za regionalni razvoj (ERDF) koji bi omogućio povlačenje čak 50 milijuna eura za Znanstvene centre izvrsnosti. Time se ozbiljno ugrožava realizacija znanstvenih aktivnosti proglašenih ZCI-a i gubitak 50 milijuna eura iz EU te zapošljavanje 300 mladih stručnjaka.

Podsjetimo, MZOS je proglasio Znanstvene centre izvrsnosti iz područja prirodnih, biomedicinskih, biotehničkih i tehničkih znanosti nakon zahtjevnih kriterija javnog natječaja, uključujući opsežne domaće i međunarodne recenzije i intervjue s voditeljima predloženih centara koji su proveli Agencija za znanost i visoko obrazovanje (AZVO) i Nacionalno vijeće za znanost, visoko obrazovanje i tehnološki razvoj. MZOS je potom temeljem članka 29. stavka 2. Zakona o znanstvenoj djelatnosti i visokom obrazovanju (Narodne novine, broj: 123/2003, 105/2004, 174/2004, 2/2007 – Odluka Ustavnog suda Republike Hrvatske, 46/2007, 45/2009,63/2011,94/2013, 139/13 i 101/2014 – Odluka i Rješenje Ustavnog suda Republike Hrvatske) proglasilo znanstvene centre izvrsnosti RH, čiji su članovi izvrsni hrvatski znanstvenici, među nositeljima međunarodne prepoznatljivosti hrvatske znanosti.

Proces prijave, vrednovanja i odabira centara trajao je tri godine, a Vlada RH je nakon provedenog postupka recenzija uskladila program centara s nacionalnim prioritetima i oni su u skladu sa Strategijom pametne specijalizacije (S3). Ovu Strategiju su više od dvije godine izrađivali brojni eksperti iz javnog i privatnog sektora koji se bave istraživanjem i razvojem, te ju je usvojio Hrvatski sabor i Europska komisija za znanost.

Cilj proglašenja centara je bio omogućiti izvrsnim hrvatskim znanstvenicima i institucijama uvjete za vrhunski istraživački rad kroz stabilno i pojačano financiranje te edukaciju mladih znanstvenika i značajan doprinos gospodarstvu RH.

Slijedom navedenog, proizlazi da se nepoštivanjem zadanih obveza od strane MZOS-a te neprovođenjem preuzetih obveza direktno ugrožavaju nacionalni interesi.

Nažalost, jedan od glavnih protivnika ustroja hrvatskih centara izvrsnosti, kao i od strane Europske komisije usvojene pametne specijalizacije (S3) RH, a koja je jedan od glavnih preduvjeta za povlačenje sredstava iz strukturnih fondova, je pomoćnik ministra za znanost dr. sc. Krešimir Zadro.

Poštovani ministre Šustar, otvorenim pismom javnosti obraćamo Vam se ispred svih Znanstvenih centara izvrsnosti (ZCI) iz područja prirodnih, biomedicinskih, biotehničkih i tehničkih znanosti sa zahtjevom da se javno očitujete o razlozima nepoštivanja odluka Vlade RH i neprovođenju usvojenih programa financiranja hrvatskih centara izvrsnosti iz EU fondova te datumu raspisivanja natječaja kako bi se izbjegao crni scenarij.

Vjerujemo da niste spremni potpuno ignorirati izvrsne hrvatske znanstvene skupine i propustiti priliku da se kroz usvojeni program pametne specijalizacije povuku sredstva u iznosu od 50 milijuna eura iz strukturnih fondova.

U situaciji kad se domaća sredstva za znanost i istraživanje sustavno režu, kad se događa egzodus najboljih mladih obrazovanih stručnjaka, znanstvena istraživanja i inovacije preživljavaju velikim dijelom zbog izvrsnosti istraživačkih skupina i velikih napora znanstvenika u povlačenju sredstva iz programa Europske unije, ovakvo opstruiranje rada Znanstvenih centara izvrsnosti da osiguraju europska sredstva za rad i zapošljavanje stručnog kadra je nedopustivo!

S poštovanjem,
voditelji proglašenih Znanstvenih centara izvrsnosti (STEM područja):

Znanstveni centar izvrsnosti za napredne materijale i senzore,
Institut Ruđer Bošković i Institut za fiziku, Zagreb

Dr. sc. Milko Jakšić – Milko.Jaksic@irb.hr
Dr. sc. Mile Ivanda – Mile.Ivanda@irb.hr
Dr. sc. Mario Stipčević – Mario.Stipcevic@irb.hr
Dr. sc. Marko Kralj – mkralj@ifs.hr

Znanstveni centar izvrsnosti za reproduktivnu i regenerativnu medicinu,

Medicinski fakultet, Sveučilište u Zagrebu,
Akademik prof. dr.sc. Slobodan Vukičević – slobodan.vukicevic@mef.hr
Prof. dr. sc. Davor Ježek – davor.jezek@mef.hr

Znanstveni centar izvrsnosti za virusnu imunologiju i cjepiva,
Medicinski fakultet, Sveučilište u Rijeci
Prof. dr. sc. Stipan Jonjić – stipan.jonjic@medri.uniri.hr

Znanstveni centar izvrsnosti za znanost i tehnologiju – STIM, Sveučilište u Splitu
Prof. dr. dr. h.c. Vlasta Bonačić-Koutecky – vbk@cms.hu-berlin.de

Znanstveni centar izvrsnosti za bioraznolikost i molekularno oplemenjivanje bilja, Agronomski fakultet , Sveučilište u Zagrebu
Prof. dr. sc. Zlatko Šatović – zsatovic@agr.hr

Znanstveni centar izvrsnosti za bioprospecting mora
Institut Ruđer Bošković, Zagreb
Dr.sc. Rozelindra Čož-Rakovac – Rozelindra.Coz-Rakovac@irb.hr

Znanstveni centar izvrsnosti za kvantne i kompleksne sustave te reprezentacije Liejevih algebri, Prirodoslovno-matematički fakultet, Sveučilište u Zagrebu

Prof.dr.sc Hrvoje Buljan – hbuljan@phy.hr
Prof. dr. sc. Pavle Pandžić – pandzic@math.hr

Znanstveni centar izvrsnosti za personaliziranu brigu o zdravlju,

Sveučilište Josip Juraj Strossmayer u Osijeku
Prof. dr. sc. Gordan Lauc – glauc@pharma.hr
Prof. dr. sc. Ines Drenjančević – ines.drenjancevic.peric@mefos.hr

Znanstveni centar izvrsnosti za temeljnu, kliničku i translacijsku neuroznanost, Medicinski fakultet, Sveučilište u Zagrebu
Prof. dr. sc. Miloš Judaš – mjudas@hiim.hr

Znanstveni centar izvrsnosti za znanost o podatcima i kooperativne sustave, Fakultet elektrotehnike i računarstva, Sveučilište u Zagrebu

Prof.dr.sc. Sven Lončarić – sven.loncaric@fer.hr
Prof. dr. sc. Ivan Petrović – ivan.petrovic@fer.hr

Priopćenje voditelja proglašenih
            Znanstvenih centara izvrsnosti (STEM područja)             ___________________________________________________________________________________________________

Manipulation of macroscopic nano-patterned graphene

  Thursday January 21st, 2016

Nano-rippled graphene is a structurally modified graphene with a large range of possible applications including sensors, electrodes, optoelectronics, spintronics, and straintronics. In this work, published in the journal Carbon 96 (2016) 243, our colleagues I. Šrut Rakić and M. Kralj from Institute of Physics, together with D. Čapeta (PMF) and M. Plodinec (IRB) have shown that it is possible to synthesize macroscopic graphene sample with well-defined uniaxial periodic modulation on a vicinal metal surface and transfer it to a dielectric support without losing nano-rippled structure.

Transfer schematics

Figure 1. (a) – (d) Schematic representation of the graphene transfer procedure steps. (e) Photograph of the Ir(332) crystal covered with graphene monolayer after the sample has been taken out of UHV. (f) Photograph of an experimental setup for the bubbling transfer. (g) Optical microscopy image (x80 magnification) of the sample during the under-potential treatment. Inset shows the magnified region marked by a black rectangle where the intercalation front indicated by a black arrow can be seen. (h) Photograph of a graphene sheet after the transfer to Si/SiO2.

Structurally modified graphene recently came into focus of graphene research bringing a promise for a wider range of possible graphene applications. The key feature of such systems is a presence of curvature in graphene typically accompanied by strain. Strain has a great effect on graphene electronic structure, conductivity, optical response, and even spin transport which can then be exploited in a rippled system for fabricating targeted optoelectronic, spintronic or generally strain facilitated electronic (straintronic) devices. Moreover, properties of the rippled graphene can be useful for various sensors, electrodes, coatings and even for hydrogen storage. Therefore, it is of great importance to be able to produce a device based on rippled graphene with well-defined uniaxial, 1D, periodic modulation. The key for making such a device is the ability to synthesize and transfer structurally modified graphene to a desirable substrate of interest.

SPM karakterizacija

Figure 2. (a) – (d) AFM topographs at several different locations at the same sample. (e) Fourier transform image of (c) confirming the 1D ordering with a periodicity of 67 nm. (f) AFM line profile corresponding to the green line in (d). Inset shows a simplified ripple cross-section used for strain calculation.

Raman characterization

Figure 3. (a) Raman spectrum of the graphene sample on Si/SiO2 recorded with an unpolarized laser light. (b) A schematic model of the polarized laser light Raman measurement. Black arrows mark laser polarization and blue arrow marks a direction of the graphene ripples. (c) Polar plot showing positions of the 2D peak with polarized light for different laser polarization angle. (d) Raman spectra of two 2D graphene peaks for two different angles of light polarization separated by 90°.

In this paper published in Carbon (IF=6.196) the authors showed that it is possible to grow periodically nano-rippled graphene on a mm scale using a prestructured stepped Ir(332) substrate. The team carried out a transfer of such 1D modulated graphene onto a Si/SiO2 wafer adapting a method called bubbling transfer (Figure 1). The key finding upon the transfer came from AFM (atomic force microscopy) characterization showing that graphene has kept its original periodic 1D rippled structure (Figure 2). Additionally, the presence of uniaxial strain in graphene was confirmed by adapting Raman spectroscopy for polarized measurements where the laser polarization was rotated in a controlled way with respect to macroscopic ripple direction, resolving between strained and unstrained directions in graphene (Figure 3).

This work presents a collaborative interinstitutional effort within the CEMS and brings a relevant achievement for a large scale graphene applications.

Projects

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Projekti

Graphene wrinkles at micro- and nano-scale

  Friday July 31st, 2015

Epitaxial graphene, considered by many as the best source of graphene for various technological applications, contains various type of defects which deteriorate its intrinsic, superior properties. The prominent defects are graphene wrinkles which are the subject of our work published in Carbon (journal IF = 6.196) this July [Carbon 94 (2015) 856-863] by M. Petrović (Institute of Physics), J.T. Sadowski (CFN BNL, USA), together with A. Šiber and M. Kralj from CEMS/G2D.

Some of the main characteristics of epitaxial graphene on metal substrates are its uniformity and high structural quality. However, due to the high synthesis temperatures and practically negligible coefficient of thermal expansion of graphene, cooling to room temperature induces stress in graphene layer. The stress is relaxed in the form of wrinkles which represent deformations of the otherwise planar graphene lattice and as such affect many properties of graphene, e.g. electrical and thermal conductivity, optical transmittance and chemical reactivity. In addition, wrinkles play a major role in graphene intercalation which is often utilized for the creation of hybrid graphene systems. Therefore, a thorough understanding of graphene wrinkles is important for potential applications of graphene.

LEEM characterizaton

(a) LEEM image of graphene’s wrinkle network, (b) Fourier transform of (a) exhibiting hexagonal symmetry, (c) polar plot of radial sums extracted from (b) and (d) illustration of graphene (orange) on Ir(111) (gray balls) with marked directions of wrinkle extension (yellow).

In the paper published in Carbon, micro- and nano-characterization of wrinkles of graphene synthesized on the iridium (111) surface has been performed. The low-energy electron microscopy (LEEM) and scanning tunneling microscopy (STM ) were used for experimental measurements and a simple analytic model was utilized for the understanding of the wrinkles’ energetics. It is shown that wrinkles, having lengths of the order of micrometers, interconnect in an ordered quasi-hexagonal network which is aligned with the substrate (see left figure). The network can be mathematically described with the aid of Voronoi diagrams, which significantly facilitates its parameterization. Also, a new model is proposed which accounts for the observed changes in the electron reflectivity of graphene and relates it to the local relaxation of the graphene lattice during wrinkle formation.

Fig2_Carbon

STM image of (a) topography and (b) first derivative of topography of graphene wrinkle and (c) wrinkle profile marked by red line in (a). Four lobes constituting the wrinkle can be identified.

Moreover, it is determined that structural details of graphene and iridium (e.g. dirt particles and already formed wrinkles) can act as nucleation centers for the formation of new wrinkles. At the nano-scale, individual wrinkles are composed of several lobes (see right figure) which result from the system frustration which is induced during cooldown from high synthesis temperatures. In terms of energy, the number of lobes is determined by the competition of the van der Waals binding acting between graphene and iridium and the graphene bending energy. Overall, this study provides new insights into graphene wrinkles and their network as a whole, which makes it relevant for future development of devices based on graphene as well as on other 2D materials.

Featured illustration by Marin Petrović.

Members

G2D core team members in alphabetical order

aumiler Damir Aumiler, Institute of Physics, investigates experimentally and theoretically the interaction of atoms with ultrashort laser pulses, starting with the ‘05 PRL paper that enabled the first frequency-domain visualization of the fs-frequency-comb and initiated the work in the field of frequency comb spectroscopy in Zagreb. Leader of the CALT structural project closely related to CEMS topics.
ban Ticijana Ban, Institute of Physics, with more than 15 years of experience in the field of experimental atomic and molecular physics works with different types of laser system from low-power cw diode laser to high power fs-laser systems. Presently, she runs the cold Rb-atoms experiment, the first ultracold experiment in Croatia and the region.
 bogdanovicradovic Iva Bogdanović Radović, Ruđer Bošković Institute, works on a development and application of different ion beam methods: Rutherford backscattering, Nuclear Reaction Analysis, Time-of-ight Elastic Recoil Detection Analysis, coincident elastic scattering and MeV Secondary Ion Mass Spectroscopy, which are relevant for materials analysis. Last couple of years she also works in a eld of materials modication by MeV ions.
 buljanH Hrvoje Buljan, Department of Physics, Faculty of Science at University of Zagreb, leader of the Modelling package, a theoretical physicist, in the past 5 years worked on plasmons in gr with a focus on plasmonic losses in these structures. The ‘09 PRB paper on this topic is by mid ’15 cited more than 450 times. Expert in the fields of optics and photonics, and ultracold atomic gases.
buljanM Maja Buljan, Ruđer Bošković Institute, works on synthesis, characterization and applications of thin films based on self-assembled nano-particles produced by magnetron sputtering. Starting with the results in PRB ‘09, which present new type of nanoparticle self-assembly process in solid amorphous systems, she works on development and application of these materials in solar cells, their characterization by X-rays and description of their growth by Monte Carlo simulations.
 gajovic Andreja Gajović, Ruđer Bošković Institute, works in the field of nanostructured functional metal oxides including syntheses and characterization of nanostructures for photo-catalysts, oxide ceramics for sensors, ferroelectrics and multiferroic. She also works on Raman spectroscopy and electron microscopy of carbon nanostructures for catalysts.
 halasz Ivan Halasz, Ruđer Bošković Institute, chemist working on mechanochemical synthesis and characterization of solid state crystalline materials. Published in prestigeous top journals such as Nature Chemistry, Angew Chem Int Ed,…
 kralj Marko Kralj, Institute of Physics, G2D research unit leader, responsible for Management & Dissemination, and Synthesis packages. He has expertise in surface physics and works on epitaxial graphene since ‘09, starting with the PRL paper and groundbreaking ARPES experiments on superlattice effects in gr which brought graphene research in Croatia to top internationally competitive level.
 lazic Predrag Lazić, Ruđer Bošković Institute, investigates novel material properties by means of density functional theory and develops new methods to describe experimental findings. The main aim is to develop improved functionals, e.g. vdW-DF in order to include nonlocal correlation crucial for the van der Waals forces playing a key role in graphene and layered 2D materials.
 siber Antonio Šiber, Institute of Physics, working on a broad range of problems in biophysics, phyical virology, soft matter physics and surface science.
 vujicic Nataša Vujičić, Institute of Physics, works in the field of experimental atomic physics and optics with more than 10 years of experience in femtosecond (fs) laser spectroscopy. Recently, she started with investigations of optical properties of 2D materials with fs lasers. Such measurements yield insights into the interactions of photoexcited carriers with other degrees of freedom, such as other carriers and phonons and  allow us to exploit the nonlinear optical response of 2D materials due to fs laser high optical intensities.
 vuletic Tomislav Vuletić, Institute of Physics, leader of the Characterization package, is continually introducing new experimental methods for soft matter physics/nanobiophysics research, consequently enabling this research eld in Croatia: development of impedance spectroscopy, fluorescence correlation spectroscopy, quartz crystal microbalance with dissipation monitoring, small angle X-ray scattering and also involvement in procurement and set-up of the AFM.

Associated members

In conjunction with the core team members, G2D research unit of CEMS has a broad network of associated members, starting from the accompanying postdocs, PhD and Masters students and researchers from around who are interested and/or are involved in 2D materials-driven topics. In the G2D unit we plan to employ additional PhD students with well-defined topics which will be aimed to make interdisciplinary connections between different topics embedded in the G2D research.

One of the most important expected impacts of the G2D unit is on young researchers. G2D will form a highly competitive school for training of young researchers with versatile skills, on timely topics, and in stimulating environment nourishing excellence. We are convinced that the students gaining PhD within G2D will be highly attractive as postdocs in top-notch world scientific institutions (for those seeking academic career this is an inevitable step), but also in Croatian SME/industry connected to the G2D and CEMS.

Equipment

@Institute of Physics

G2Dcorridor_20151125_6

Corridor in the second wing of the Institute of Physics hosting several G2D labs and offices: 122/II-125/II, 132/II-135/II.

Institute of Physics (IFZ) is the G2D unit of CEMS host institution. The expertise from members at IFZ (solid state physics, surface science, biological physics, atomic, molecular, optical and plasma physics) secures accessibility of capital equipment existing at IFZ in particular the core team members labs: scanning probe techniques STM and AFM under ambient and in vacuum, photoelectron spectroscopy and electron diffraction in vacuum, SAXS/GISAXS X-ray techniques, bio and planar sample fabrication, dielectric spectroscopy, flourescence correlation spectroscopy, femtosecond laser spectroscopy, …

@Ruđer Bošković and Physics Department

The versatility of expertise at IFZ is complemented by the equipment in labs of core members from Ruđer Bošković Institute and Physics Department at Faculty of Science: Raman spectroscopy, scanning and transmission electron microscopy, RBI accelerator facility, GISAX and its modelling, magnetron sputtering, mechanochemistry lab, computational infrastructure, …

@New capital equipment

The aim of the G2D unit is to modernize and upgrade equipment across the teams and in particular to develop new labs which will add value to the joined expertise of team members. The main two new labs to be established within the G2D unit: (1) The “CVD Lab”, based on ~2-3 inch diameter variable pressure CVD furnace and accessories, will enable us routine synthesis of large amounts of monolayer samples, which at the moment we synthesize on smaller scale below 1 inch; (2) “Laboratory for Extreme Mechanics” will enable us to study elasticity phenomena and processes intrinsic to graphene and other (macroscopically) elastic materials.

Talks and Publications

Invited conference talks

Chemical and mechanical nanoengineering of (epitaxial) graphene, M. Kralj @ Energy Materials and Nanotechnology Qingdao Meeting, Qingdao, China (14.-17.6.2015.)

Epitaksijalni grafen i srodni 2D materijali, M. Kralj @ 9. znanstveni sastanak Hrvatskog fiziklanog društva, Umag, Croatia (5.-7.10.2015.)

Graphene Applications, M. Kralj @ Inovation – Driven Defence Enterprising, Zagreb, Croatia (19.-20.10.2015.)

Selected seminars and colloquia

Chemical and mechanical engineering of epitaxial graphene, 25.3.2015, talk by M. Kralj at Physik-Institut, University of Zurich, Zurich, Switzerland (invited by Thomas Greber)

Engineering epitaxial graphene by adsorption, intercalation and strain, 3.6.2015, talk by M. Kralj at NUS Centre for Advanced 2D Materials, National University of Singapore, Singapore (invited by Slaven Garaj)

Aspects of epitaxial graphene engineering: adsorption, intercalation, strain, and transfer, 10.6.2015, talk by M. Kralj at Institute of Physics, Chinese Academy of Sciences, Beijing, China (invited by Hongjun Gao / Ye-Liang Wang)

Primjene epitaksijalnog grafena: adsorpcija, interkalacija, elastičnost, 13.07.2015., talk by M. Kralj at Mediterranean Institute for Life Sciences, Split, Croatia (invited by Vlasta Bonačić-Koutecky)

Selected publications

Intercalated boosters, M. Kralj, Nature Physics 11 (2015) 11–12

Electrochemical Reaction in Single Layer MoS2: Nanopores Opened Atom by Atom, J. Feng, K. Liu, M. Graf, M. Lihter, R. D. Bulushev, D. Dumcenco, D.T.L. Alexander, D. Krasnozhon, T. Vuletić, A. Kis, A. Radenovic, Nano Letters 15 (2015) 3431–3438

Charge Photogeneration in Few-Layer MoS2, T. Borzda, C. Gadermaier, N. Vujičić, et al., Advanced Functional Materials 25 (2015) 3351–3358

Wrinkles of graphene on Ir(111): Macroscopic network ordering and internal multi-lobed structure, M. Petrović, J.T. Sadowski, A. Šiber, M. Kralj, Carbon 94 (2015) 856–863

Self-assembly of Ge quantum dots on periodically corrugated Si surfaces, M. Buljan, S. Facsko, I. Delač Marion, V. Mikšić Trontl, M. Kralj, M. Jerčinović, C. Baehtz, A. Muecklich, V. Holy, N. Radić, J. Grenzer, Applied Physics Letters 107 (2015) 203101

Large-scale transfer and characterization of macroscopic periodically nano-rippled graphene, I. Šrut Rakić, D. Čapeta, M. Plodinec, M. Kralj, Carbon 96 (2016) 243–249

Research topics

G2D mosaic green_LRThe G2D draws its strength upon synergy of researchers with versatile expertise in condensed matter physics, optics and photonics, soft-matter physics, solid state chemistry, ion-beam physics, and material science. This expertise and synergy provides a promise for discoveries of new phenomena in 2D materials, and potentially their applications. Particular topics to be investigated aim at (opto)mechanical, optoelectronic, spintronic, bioelectronic, capacitor, and photovoltaic applications.

Synthesis

All large scale applications require synthesis (in large amounts) of large area 2D materials. We will explore and improve different methods of synthesis. The CVD method will be exploited under various conditions (vacuum, low pressure, atmospheric pressure) and optimised for the growth of large area (~few cm2) graphene, TMD, and h-BN single-crystal layers on metallic and other types of substrates; we will develop methods of functionalization (modify shapes, electronic properties, etc…) in electronic, optoelectronic and bioelectronic devices. We will develop transfer procedures based on novel carrier polymers and solvents which were not yet exploited, in order to obtain high-quality devices for characterization of optical and (opto)mechanical properties or to obtain high-quality electrode for solar cells. We will also develop mechanochemical methods to synthesize large amounts of 2D material, which offers greater control of the reaction course over traditional methods by establishing novel methods of high-throughput synthesis e.g. for the optimization of graphene anode in supercapacitors. Finally, we plan to produce more complex samples and by this we aim at specific properties and functionality of these complex structures. This will involve production of hybrid structures like DNA arrays on template graphene; samples and devices intercalated by magnetic or other desired proximity property materials; heterostructures obtained by combination of graphene and/or TMD and/or h-BN layers; transparent electrodes for quantum-dots based novel photovoltaic applications; defect engineered graphene and 2D materials.

Characterization

We apply a broad chain of characterization methods aiming at different physical properties. Basic sample characterization is provided through the application of Raman micro spectroscopy (Raman), scanning- and transmission-electron microscopy (SEM, TEM), scanning tunneling and atomic force microscopy (STM, AFM) characterization, and additional techniques, such as x-ray diffraction, or grazing incidence small angle x-ray scattering. In addition, more specialized experiments are envisioned to explore: optical properties of 2D materials (photodetection, photoluminescence, photoexcited carriers); macroscopic elastic properties, e.g. wrinkles and more complicated forms in porous graphite with an experimental insight obtained in newly established Laboratory for extreme mechanics; electronic transport and electronic band structure of different samples by transport methods and photoelectron spectroscopies; efficiency of 2D materials as electrodes in the photovoltaic elements; performance of graphene anode obtained from high-throughput synthesis; porosimetry for samples relevant for gas storing.

Modelling

Theoretical calculations are performed to study various electric, optical and mechanical properties of graphene and 2D materials by using the most up-to-date methods and techniques including DFT calculations (numerical), density-matrix theory calculation of the AC conductivity (perturbation theory), finite-difference time-domain Maxwell equations (numerical calculation of the optical properties of graphene based devices), and theory of elasticity (mechanical properties). In addition, for more complex structures e.g. transistors, electrodes such as gates will be implemented in vdW-DF methodology to model or predict properties of rechargeable batteries, solar cell materials, thermoelectrics and so on.

Science of Graphene and Related 2D Structures

G2D_scheme_LRThe mission of the CEMS research unit Science of Graphene and Related 2D Structures (G2D) is to provide a framework for highly competitive level of research on the international level, which is focused on graphene and related 2D materials, to gather a team of scientists
capable of acquiring funding from most competitive EU and other international funding sources, and to promote research motivated by applications of direct interest for the Croatian hi-tech, SME, and industrial sectors. The synergy of the G2D and CEMS as a whole is ubiquitous for achieving those objectives.

The scientific focus of the G2D is on graphene, a 2D crystal of carbon atoms arranged in a honeycomb lattice, and follow-up 2D materials which complement graphene and extend versatility regarding physical and chemical properties and related applications. The research on graphene runs at an intensive pace for almost a decade now, being one of the most active fields in today’s scientific research in general. The potential of 2D materials to revolutionize technologies was recognized globally, which poured considerable research funding around this topic. For example, the Graphene flagship programme by the EU invests one billion Euro in the period 2013-2023 specifically in a direction of future emerging technologies (FET) based on graphene and follow-up 2D materials.

The capacities of the team are based on our own research results on graphene, which stands on equal footing with respect to industrially far more developed countries, as well as on a broad expertise concentrated in the team in versatile topics that can be streamed towards 2D materials-related topics. This enabled us to develop a concept based on a closed cycle of research involving different types of innovative synthesis, a broad range of characterization methods and a strong support in theoretical modelling, thus granting for G2D’s independence and open innovativeness. The strength of the team should be emphasized. All team members are in the middle or early stage of their career, highly productive, with the track records ranking them among top scientists in Croatia.