0000000000483565
AUTHOR
Margarita Baitimirova
showing 14 related works from this author
Catalyst-free vapour-solid technique for deposition of Bi2Te3 and Bi2Se3 nanowires/nanobelts with topological insulator properties.
2015
We present a simple two-stage vapour–solid synthesis method for the growth of bismuth chalcogenide (Bi2Te3, Bi2Se3) topological insulator nanowires/nanobelts by using Bi2Se3 or Bi2Te3 powders as source materials. During the first stage of the synthesis process nanoplateteles, serving as “catalysts” for further nanowire/nanobelt growth, are formed. At a second stage of the synthesis, the introduction of a N2 flow at 35 Torr pressure in the chamber induces the formation of free standing nanowires/nanobelts. The synthesised nanostructures demonstrate a layered single-crystalline structure and Bi : Se and Bi : Te ratios 40 : 60 at% for both Bi2Se3 and Bi2Te3 nanowires/nanobelts. The presence of…
Deformation behavior and interfacial sliding in carbon/copper nanocomposite films deposited by high power DC magnetron sputtering
2015
Abstract Amorphous carbon–copper nanocomposite films with a carbon content from 7 to 40 at.% have been deposited onto steel, silicon and glass substrates using a high power (> 60 W/cm 2 ) and high-rate DC magnetron sputtering technique. XRD, Raman spectroscopy and TEM results confirm that the deposited films consist of copper nanograins (size
Structure and Doping Determined Thermoelectric Properties of Bi2Se3Thin Films Deposited by Vapour–Solid Technique
2019
In this work, a simple catalyst-free vapour-solid deposition method was applied for controlled deposition of two types (planar and disordered) of continuous Bi 2 Se 3 nanostructured thin films on different (fused quartz/glass, mica, graphene) substrates. Characterisation of electron transport (type, concentration and mobility of the main charge carriers) and thermoelectric properties (Seebeck coefficient and power factor) showed that proposed in this work deposition method allows to obtain Bi 2 Se 3 thin films with power factor comparable and even higher than reported for the Bi 2 Se 3 thin films grown by molecular beam epitaxy technique. Power factor of the best obtained thin films can be …
Surface structure promoted high-yield growth and magnetotransport properties of Bi2Se3 nanoribbons
2019
AbstractIn the present work, a catalyst-free physical vapour deposition method is used to synthesize high yield of Bi2Se3 nanoribbons. By replacing standard glass or quartz substrates with aluminium covered with ultrathin porous anodized aluminium oxide (AAO), the number of synthesized nanoribbons per unit area can be increased by 20–100 times. The mechanisms of formation and yield of the nanoribbons synthesized on AAO substrates having different arrangement and size of pores are analysed and discussed. It is shown that the yield and average length of the nanoribbons can base tuned by adjustment of the synthesis parameters. Analysis of magnetotransport measurements for the individual Bi2Se3…
Improved Crystalline Structure and Enhanced Photoluminescence of ZnO Nanolayers in Bi2Se3/ZnO Heterostructures
2019
The Bi2Se3/ZnO heterostructure is a new combination of high- and low-band-gap nanomaterials that can be implemented for optoelectronic devices. The influence of the Bi2Se3 substrate on crystallizat...
Role of Nanoelectromechanical Switching in the Operation of Nanostructured Bi2Se3 Interlayers between Conductive Electrodes
2016
We demonstrate a simple low-cost method of preparation of layered devices for opto- and thermoelectric applications. The devices consist of a functional Bi2Se3 layer of randomly oriented nanoplates and flexible nanobelts enclosed between two flat indium tin oxide (ITO) electrodes. The number of functional interconnections between the ITO electrodes and correspondingly the efficiency of the device can be increased by gradual nanoelectromechanical (NEM) switching of flexible individual Bi2Se3 nanobelts in the circuit. NEM switching is achieved through applying an external voltage to the device. For the first time, we investigate in situ NEM switching and breakdown parameters of Bi2Se3 nanobel…
Tuning of Structural and Optical Properties of Graphene/ZnO Nanolaminates
2016
International audience; Zinc Oxide (ZnO) and graphene (G) have been extensively studied because of their unique physical properties. Here, Graphene-Zinc Oxide (G/ZnO) nanolaminates were fabricated, respectively, by chemical vapor deposition and low temperature atomic layer deposition technique. The number of obtained G/ZnO layers was tuned from 1 to 11 with a total thickness of 100 nm for all prepared nanolaminates. The structure, optical properties and interaction between G and ZnO were studied by X-ray methods, TEM, AFM, Raman and optical spectroscopy. The obtained results were interpreted and analysed taking into account strain and charge effects of graphene in G/ZnO nanostructures. We d…
Structure-determined thermoelectric properties of Bi2Se3 thin films deposited by vapour-solid technique
2018
International audience; In this work, a simple catalyst-free vapour-solid deposition method is applied for controlled obtaining of two types (planar and disordered) continuous Bi2Se3 nanostructured thin films on different (fused quartz/glass, mica, graphene) substrates. Performed for the deposited thin films transport and thermoelectric characterization (type, concentration and mobility of the main charge carriers, Seebeck coefficient and power factor) showed that proposed deposition method allows to fabricate “low-doped” Bi2Se3 thin films with power factor comparable and even higher than reported for the Bi2Se3 thin films fabricated by molecular beam epitaxy technique.
Characterization of functional groups of airborne particulate matter
2013
Particulate matter of organic combustibles burning consists of various hydrocarbons and radicals, which may cause harmful impact to human health. In this study solid particulate matter were collected on the filters from burning of various combustibles in a burning chamber and from atmosphere of city of Riga by dichotomous impactor. FTIR spectra were obtained before and after samples' treatment. Absorptions associated with aliphatic and aromatic hydrocarbons and alcohol functional groups were observed in the FTIR spectra. Free radicals of particulate matter were detected by electron paramagnetic resonance (EPR).
Effect of graphene substrate type on formation of Bi2Se3 nanoplates
2019
AbstractKnowledge of nucleation and further growth of Bi2Se3 nanoplates on different substrates is crucial for obtaining ultrathin nanostructures and films of this material by physical vapour deposition technique. In this work, Bi2Se3 nanoplates were deposited under the same experimental conditions on different types of graphene substrates (as-transferred and post-annealed chemical vapour deposition grown monolayer graphene, monolayer graphene grown on silicon carbide substrate). Dimensions of the nanoplates deposited on graphene substrates were compared with the dimensions of the nanoplates deposited on mechanically exfoliated mica and highly ordered pyrolytic graphite flakes used as refer…
Influence of ZnO/graphene nanolaminate periodicity on their structural and mechanical properties
2018
International audience; Structural, electronic and mechanical properties of ZnO/Graphene (ZnO/G) nanolaminates fabricated by low temperature atomic layer deposition (ALD) and chemical vapor deposition (CVD) were investigated. We performed scanning and transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), Raman spectroscopy, X-Ray photoelectron spectroscopy (XPS) and nanoindentation to characterize the ZnO/G nanolaminates. The main structural and mechanical parameters of ZnO/G nanolaminates were calculated. The obtained results were analyzed and interpreted taking into account mechanical interaction and charge effects occurring at the …
Gaisa aerosolu daļiņu elektroķīmiskās impedances spektru analīze
2011
Darbā veikta elektroķīmiskās impedances spektru analīze Rīgas pilsētvides gaisa smalkajām un rupjajām aerosolu daļiņām, kas uzkrātas uz stikla šķiedras filtriem. Pēc aerosolu daļiņu paraugu priekšapstrādes tika uzņemtas cikliskās voltamperogrammas, impedances spektri un dubultslāņa kapacitātes spektri. Impedances spektru analīzei izmantota ekvivalento shēmu metode un statistiskā metode. Analizējot impedances un dubultslāņa kapacitātes spektrus, novērtēta aerosolu daļiņu izmēra, piesārņojuma, ogles un pārējo sastāvdaļu ietekme uz parauga virsmas raksturu.
Cieto aerosolu daļiņu ķīmiskais un elektroķīmiskais raksturojums
2013
Darbā ir pētītas cietas aerosolu daļiņas, ievāktas no Rīgas pilsētas atmosfēras un no dūmiem, kas rodas dedzinot dažādus kurināmos. Daļiņu ievākšana tika veikta ar dihotomo impaktoru un ar laboratorijā izveidoto slēgto dedzināšanas kameru. Furjē transformācijas infrasarkanie spektri un elektronu paramagnētiskās rezonanses spektri tika uzņemti pirms un pēc paraugu ķīmiskās apstrādes. Aerosolu daļiņu struktūra tika apskatīta skenējošā elektronu mikroskopā. Daļiņām tika mērīts ζ-potenciāls ar laboratorijā izveidoto aparātu.
Grafēnu saturošo slāņainu nonostruktūru veidošana un to īpašību pētījumi
2022
Promocijas darbs ir veltīts jaunu, uz unikālā materiāla –grafēna(G)balstītu slāņainu nanomateriālu ar uzlabotu struktūru, optiskām un termoelektriskām īpašībām izveidošanai, to pārbaudei pielietojumam elektroniskās, termoelektriskās un fotojutīgāsierīcēs. Darbā izstrādātas metodikas termoelektriskā (TE) materiāla Bi2Se3atsevišķu nanostruktūru un nanostrukturēto pārklājumu sintēzei uz dažādām virsmām (stikls, kvarcs, G, ITO, AAO). Izveidots TEierīces prototips, balstīts uz Bi2Se3nanostrukturētā pārklājumu, ieslēgtu starp diviem Gslāņiem. Pirmo reizi ir izveidoti G/ZnOnanolamināti ar dažādu Gstarpslāņu skaitu un ZnOslāņu biezumu. Izpētītas šo struktūru kristāliskās un optiskās īpašības atkarī…