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Yakimova, Rositsa
Alternative names
Publications (10 of 394) Show all publications
Shavanova, K., Bakakina, Y., Burkova, I., Shtepliuk, I., Viter, R., Ubelis, A., . . . Khranovskyy, V. (2016). Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology. Sensors, 16(2)
Open this publication in new window or tab >>Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology
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2016 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, no 2Article, review/survey (Refereed) Published
Abstract [en]

The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

Place, publisher, year, edition, pages
MDPI AG, 2016
Keywords
transition metal dichalcogenides; transducers; beyond graphene; biosensors; two-dimensional materials; two-dimensional oxides; transition metal oxides
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-126850 (URN)10.3390/s16020223 (DOI)000371787800102 ()26861346 (PubMedID)
Note

Funding Agencies|EC FP-7 International Research Staff Exchange Scheme (IRSES) Grant [318520]; Linkoping Linnaeus Initiative for Novel Functional Materials (LiLi-NFM); European Union [604391]; Swedish Research Council (VR) Marie Sklodowska Curie International Career Grant [2015-00679]

Available from: 2016-04-05 Created: 2016-04-05 Last updated: 2017-11-30
Beshkova, M., Hultman, L. & Yakimova, R. (2016). Device applications of epitaxial graphene on silicon carbide. Vacuum, 128, 186-197
Open this publication in new window or tab >>Device applications of epitaxial graphene on silicon carbide
2016 (English)In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 128, p. 186-197Article, review/survey (Refereed) Published
Abstract [en]

Graphene has become an extremely hot topic due to its intriguing material properties allowing for ground-breaking fundamental research and applications. It is one of the fastest developing materials during the last several years. This progress is also driven by the diversity of fabrication methods for graphene of different specific properties, size, quantity and cost. Graphene grown on SiC is of particular interest due to the possibility to avoid transferring of free standing graphene to a desired substrate while having a large area SiC (semi-insulating or conducting) substrate ready for device processing. Here, we present a review of the major current explorations of graphene on SiC in electronic devices, such as field effect transistors (FET), radio frequency (RF) transistors, integrated circuits (IC), and sensors. The successful role of graphene in the metrology sector is also addressed. Typical examples of graphene on SiC implementations are illustrated and the drawbacks and promises are critically analyzed. (C) 2016 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2016
Keywords
Graphene FET; RF-transistors; IC; Graphene sensors; Detectors; Quantum Hall resistance
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-129150 (URN)10.1016/j.vacuum.2016.03.027 (DOI)000376052500026 ()
Note

Funding Agencies|European Union [604391]; Swedish Research Council [VR 621-2014-5805]; LiU Linnaeus Grant

Available from: 2016-06-13 Created: 2016-06-13 Last updated: 2017-11-28
Shtepliuk, I., Khranovskyy, V. & Yakimova, R. (2016). Effect of c-axis inclination angle on the properties of ZnO/Zn1-xCdxO/ZnO quantum wells. Thin Solid Films, 603, 139-148
Open this publication in new window or tab >>Effect of c-axis inclination angle on the properties of ZnO/Zn1-xCdxO/ZnO quantum wells
2016 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 603, p. 139-148Article in journal (Refereed) Published
Abstract [en]

The development of optoelectronic devices based on highly-promising Zn1 - xCdxO semiconductor system demands deep understanding of the properties of the Zn1 - xCdxO-based quantum wells (QWs). In this regard, we carried out a numerical study of the polarization-related effects in polar, semi-polar and non-polar ZnO/ Zn1 - xCd xO/ZnO QWs with different parameters of the quantum well structure. The effects of well width, barrier thickness, cadmium content in the active layer and c-axis inclination angle on the distribution of the electron and hole wave function and transition energy were investigated using the 6 x 6 k center dot p Hamiltonian and one-dimensional self-consistent solutions of nonlinear Schrodinger-Poisson equations with consideration of spatially varying dielectric constant and effective mass. The strong sensitivity of the internal electric field, transition energy and overlap integral to cadmium content and well thickness in the angle range from 0 to 40 degrees was revealed. An unexpected change of the internal electric fields sign was observed at the angles ranging from 70 to 90 degrees. We also found a difference in the electronic properties between (0001)-, (11 (2) over bar2)-and (10 (1) over bar0)-oriented QWs.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2016
Keywords
Inclination angle; Quantum well; Polarization; ZnCdO alloy; Transition energy
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-127431 (URN)10.1016/j.tsf.2016.02.007 (DOI)000372794900022 ()
Note

Funding Agencies|Swedish Institute scholarship

Available from: 2016-05-01 Created: 2016-04-26 Last updated: 2017-11-30
Yazdi, G., Iakimov, T. & Yakimova, R. (2016). Epitaxial Graphene on SiC: A Review of Growth and Characterization. Crystals, 6(5), Article ID 53.
Open this publication in new window or tab >>Epitaxial Graphene on SiC: A Review of Growth and Characterization
2016 (English)In: Crystals, ISSN 2073-4352, Vol. 6, no 5, article id 53Article, review/survey (Refereed) Published
Abstract [en]

This review is devoted to one of the most promising two-dimensional (2D) materials, graphene. Graphene can be prepared by different methods and the one discussed here is fabricated by the thermal decomposition of SiC. The aim of the paper is to overview the fabrication aspects, growth mechanisms, and structural and electronic properties of graphene on SiC and the means of their assessment. Starting from historical aspects, it is shown that the most optimal conditions resulting in a large area of one ML graphene comprise high temperature and argon ambience, which allow better controllability and reproducibility of the graphene quality. Elemental intercalation as a means to overcome the problem of substrate influence on graphene carrier mobility has been described. The most common characterization techniques used are low-energy electron microscopy (LEEM), angle-resolved photoelectron spectroscopy (ARPES), Raman spectroscopy, atomic force microscopy (AFM) in different modes, Hall measurements, etc. The main results point to the applicability of graphene on SiC in quantum metrology, and the understanding of new physics and growth phenomena of 2D materials and devices.

Place, publisher, year, edition, pages
MDPI AG, 2016
Keywords
graphene; epitaxial; SiC; sublimation
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-129674 (URN)10.3390/cryst6050053 (DOI)000377262000006 ()
Note

Funding Agencies|European Union Seventh Framework Program [604391]; Swedish Research Council [VR 621-2014-5805]; SSF; KAW funding

Available from: 2016-06-27 Created: 2016-06-23 Last updated: 2017-11-28
Alexander-Webber, J. A., Huang, J., Maude, D. K., Janssen, T. J., Tzalenchuk, A., Antonov, V., . . . Nicholas, R. J. (2016). Giant quantum Hall plateaus generated by charge transfer in epitaxial graphene. Scientific Reports, 6(30296)
Open this publication in new window or tab >>Giant quantum Hall plateaus generated by charge transfer in epitaxial graphene
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2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, no 30296Article in journal (Refereed) Published
Abstract [en]

Epitaxial graphene has proven itself to be the best candidate for quantum electrical resistance standards due to its wide quantum Hall plateaus with exceptionally high breakdown currents. However one key underlying mechanism, a magnetic field dependent charge transfer process, is yet to be fully understood. Here we report measurements of the quantum Hall effect in epitaxial graphene showing the widest quantum Hall plateau observed to date extending over 50 T, attributed to an almost linear increase in carrier density with magnetic field. This behaviour is strong evidence for field dependent charge transfer from charge reservoirs with exceptionally high densities of states in close proximity to the graphene. Using a realistic framework of broadened Landau levels we model the densities of donor states and predict the field dependence of charge transfer in excellent agreement with experimental results, thus providing a guide towards engineering epitaxial graphene for applications such as quantum metrology.

Place, publisher, year, edition, pages
Nature Publishing Group, 2016
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-130834 (URN)10.1038/srep30296 (DOI)000380203800001 ()27456765 (PubMedID)
External cooperation:
Note

Funding Agencies|UK EPSRC; Graphene Flagship [CNECT-ICT-604391]; EMRP project GraphOhm; AFRL grant [FA9550-15-C-0067]; LNCMI-CNRS; International Collaborative Energy Technology R&D Program of the Korean Institute of Energy Technology Evaluation and Planning (KETEP); Ministry of Trade, Industry & Energy, Republic of Korea [20148520011250]

Available from: 2016-08-26 Created: 2016-08-26 Last updated: 2017-11-21Bibliographically approved
Jokubavicius, V., Sun, J., Liu, X., Yazdi, G., Ivanov, I. G., Yakimova, R. & Syväjärvi, M. (2016). Growth optimization and applicability of thick on-axis SiC layers using sublimation epitaxy in vacuum. Journal of Crystal Growth, 448, 51-57
Open this publication in new window or tab >>Growth optimization and applicability of thick on-axis SiC layers using sublimation epitaxy in vacuum
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2016 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 448, p. 51-57Article in journal (Refereed) Published
Abstract [en]

We demonstrate growth of thick SiC layers (100–200 µm) on nominally on-axis hexagonal substrates using sublimation epitaxy in vacuum (10−5 mbar) at temperatures varying from 1700 to 1975 °C with growth rates up to 270 µm/h and 70 µm/h for 6H- and 4H–SiC, respectively. The stability of hexagonal polytypes are related to process growth parameters and temperature profile which can be engineered using different thermal insulation materials and adjustment of the induction coil position with respect to the graphite crucible. We show that there exists a range of growth rates for which single-hexagonal polytype free of foreign polytype inclusions can be maintained. Further on, foreign polytypes like 3C–SiC can be stabilized by moving out of the process window. The applicability of on-axis growth is demonstrated by growing a 200 µm thick homoepitaxial 6H–SiC layer co-doped with nitrogen and boron in a range of 1018 cm−3 at a growth rate of about 270 µm/h. Such layers are of interest as a near UV to visible light converters in a monolithic white light emitting diode concept, where subsequent nitride-stack growth benefits from the on-axis orientation of the SiC layer.

Keywords
Mass transfer;Substrates;Single crystal growth;Semiconducting materials
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-128610 (URN)10.1016/j.jcrysgro.2016.05.017 (DOI)
Available from: 2016-05-25 Created: 2016-05-25 Last updated: 2017-11-30
Pallon, J., Syväjärvi, M., Wang, Q., Yakimova, R., Iakimov, T., Elfman, M., . . . Ros, L. (2016). Ion beam evaluation of silicon carbide membrane structures intended for particle detectors. Paper presented at 22nd International Conference on Ion Beam Analysis (IBA). Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 371, 132-136
Open this publication in new window or tab >>Ion beam evaluation of silicon carbide membrane structures intended for particle detectors
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2016 (English)In: Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, ISSN 0168-583X, E-ISSN 1872-9584, Vol. 371, p. 132-136Article in journal (Refereed) Published
Abstract [en]

Thin ion transmission detectors can be used as a part of a telescope detector for mass and energy identification but also as a pre-cell detector in a microbeam system for studies of biological effects from single ion hits on individual living cells. We investigated a structure of graphene on silicon carbide (SiC) with the purpose to explore a thin transmission detector with a very low noise level and having mechanical strength to act as a vacuum window. In order to reach very deep cavities in the SiC wafers for the preparation of the membrane in the detector, we have studied the Inductive Coupled Plasma technique to etch deep circular cavities in 325 mu m prototype samples. By a special high temperature process the outermost layers of the etched SiC wafers were converted into a highly conductive graphitic layer. The produced cavities were characterized by electron microscopy, optical microscopy and proton energy loss measurements. The average membrane thickness was found to be less than 40 mu m, however, with a slightly curved profile. Small spots representing much thinner membrane were also observed and might have an origin in crystal defects or impurities. Proton energy loss measurement (also called Scanning Transmission Ion Microscopy, STIM) is a well suited technique for this thickness range. This work presents the first steps of fabricating a membrane structure of SiC and graphene which may be an attractive approach as a detector due to the combined properties of SiC and graphene in a monolithic materials structure. (C) 2015 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2016
Keywords
Transmission detector; Graphene; ICP; Nuclear microprobe
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-127570 (URN)10.1016/j.nimb.2015.10.045 (DOI)000373412000025 ()
Conference
22nd International Conference on Ion Beam Analysis (IBA)
Available from: 2016-05-04 Created: 2016-05-03 Last updated: 2017-11-30
Khranovskyy, V., Shtepliuk, I., Ivanov, I. G., Tsiaoussis, I. & Yakimova, R. (2016). Light emission enhancement from ZnO nanostructured films grown on Gr/SiC substrates. Carbon, 99, 295-301
Open this publication in new window or tab >>Light emission enhancement from ZnO nanostructured films grown on Gr/SiC substrates
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2016 (English)In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 99, p. 295-301Article in journal (Refereed) Published
Abstract [en]

We report on the application of a single layer graphene substrates for the growth of polycrystalline ZnO films with advanced light emission properties. Unusually high ultraviolet (UV) and visible (VIS) photoluminesce was observed from the ZnO/Gr/SiC structures in comparison to identical samples without graphene. The photoluminescence intensity depends non-monotonically on the films thickness, reaching its maximum for 150 nm thick films. The phenomena observed is explained as due to the dual graphene role: i) the dangling bond free substrate, providing growth of relaxed thin ZnO layers ii) a back reflector active mirror of the Fabry-Perot cavity that is formed. The reported results demonstrate the potential of two-dimensional carbon materials integration with light emitting wide band gap semiconductors and can be of practical importance for the design of future optoelectronic devices.

Place, publisher, year, edition, pages
Pergamon Press, 2016
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-123947 (URN)10.1016/j.carbon.2015.12.010 (DOI)000369069800035 ()
Note

Funding agencies:  Linkoping Linnaeus Initiative for Novel Functional Materials (LiLi-NFM); Angpanneforeningens Forskningsstiftelse [14-517]; European Union [604391]

Available from: 2016-01-14 Created: 2016-01-14 Last updated: 2017-11-30Bibliographically approved
Eriksson, J., Puglisi, D., Strandqvist, C., Gunnarsson, R., Ekeroth, S., Ivanov, I. G., . . . Lloyd Spetz, A. (2016). Modified Epitaxial Graphene on SiC for Extremely Sensitive andSelective Gas Sensors. Paper presented at ICSCRM 2015, The International Conference on Silicon Carbide and Related Materials, 4-9 October 2015, Giardini Naxos, Italy. Materials Science Forum, 858, 1145-1148
Open this publication in new window or tab >>Modified Epitaxial Graphene on SiC for Extremely Sensitive andSelective Gas Sensors
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2016 (English)In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 858, p. 1145-1148Article in journal (Refereed) Published
Abstract [en]

Two-dimensional materials offer a unique platform for sensing where extremely high sensitivity is a priority, since even minimal chemical interaction causes noticeable changes inelectrical conductivity, which can be used for the sensor readout. However, the sensitivity has to becomplemented with selectivity, and, for many applications, improved response- and recovery times are needed. This has been addressed, for example, by combining graphene (for sensitivity) with metal/oxides (for selectivity) nanoparticles (NP). On the other hand, functionalization or modification of the graphene often results in poor reproducibility. In this study, we investigate thegas sensing performance of epitaxial graphene on SiC (EG/SiC) decorated with nanostructured metallic layers as well as metal-oxide nanoparticles deposited using scalable thin-film depositiontechniques, like hollow-cathode pulsed plasma sputtering. Under the right modification conditions the electronic properties of the surface remain those of graphene, while the surface chemistry can betuned to improve sensitivity, selectivity and speed of response to several gases relevant for airquality monitoring and control, such as nitrogen dioxide, benzene, and formaldehyde.

Place, publisher, year, edition, pages
Trans Tech Publications Inc., 2016
Keywords
Epitaxial graphene, graphene hybrid materials, gas sensor
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-128078 (URN)10.4028/www.scientific.net/MSF.858.1145 (DOI)
Conference
ICSCRM 2015, The International Conference on Silicon Carbide and Related Materials, 4-9 October 2015, Giardini Naxos, Italy
Available from: 2016-05-16 Created: 2016-05-16 Last updated: 2018-03-26
Tereshchenko, A., Bechelany, M., Viter, R., Khranovskyy, V., Smyntyna, V., Starodub, N. & Yakimova, R. (2016). Optical biosensors based on ZnO nanostructures: advantages and perspectives. A review. Sensors and actuators. B, Chemical, 229, 664-677
Open this publication in new window or tab >>Optical biosensors based on ZnO nanostructures: advantages and perspectives. A review
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2016 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 229, p. 664-677Article, review/survey (Refereed) Published
Abstract [en]

This review article highlights the application of beneficial physico-chemical properties of ZnO nanostructures for the detection of wide range of biological compounds. As the medical diagnostics require accurate, fast and inexpensive biosensors, the advantages inherent optical methods of detection are considered. The crucial points of the immobilization process, responsible for biosensor performance (biomolecule adsorption, surface properties, surface defects role, surface functionalization etc.) along with the interaction mechanism between biomolecules and ZnO are disclosed. The latest achievements in surface plasmon resonance (SPR), surface enhanced Raman spectroscopy (SERS) and photoluminescence based biosensors along with novel trends in the development of ZnO biosensor platform are presented. (c) 2016 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2016
Keywords
Optical biosensors; ZnO; Nanostructures; Immobilization; Photoluminescence based biosensors; Interaction mechanism
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-127247 (URN)10.1016/j.snb.2016.01.099 (DOI)000372525400077 ()
Note

Funding Agencies|EC [318520]

Available from: 2016-04-22 Created: 2016-04-19 Last updated: 2017-11-30
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