Number of found documents: 528
Published from to

Room temperature ethanol detection using carbon materials
Kočí, Michal
2023 - English
Allotropic forms of carbon, in particular graphene oxide (GO) or nanocrystalline diamond (NCD), attracted the attention of many research groups due to their unique electronic structures and extraordinary physical and chemical properties, preferable for many different applications, including sensor devices. This work focuses on responses of various sensing layers (NCD with hydrogen termination (H-NCD), graphene oxide (GO), reduced graphene oxide (rGO), thiol-functionalized graphene oxide (GO-SH) and their hybrid structures to ethanol vapor with concentrations up to 100 ppm in synthetic air at room temperature. The measured parameters of the tested sensors, especially stability, reproducibility and regeneration, are compared and critically evaluated. The high sensitivity of tested sensors achieved at room temperature makes them very promising for monitoring ethanol vapor as well as other volatile substances (e.g., isopropyl-alcohol or acetone). Keywords: gas sensor; nanocrystalline diamond (NCD); graphene oxide (GO); reduced graphene oxide (rGO); thiol-functionalized graphene oxide (GO-SH) Available at various institutes of the ASCR
Room temperature ethanol detection using carbon materials

Allotropic forms of carbon, in particular graphene oxide (GO) or nanocrystalline diamond (NCD), attracted the attention of many research groups due to their unique electronic structures and ...

Kočí, Michal
Fyzikální ústav, 2023

Technological challenges in the fabrication of MoS.sub.2./sub./diamond heterostructures
Varga, Marián; Sojková, M.; Hrdá, J.; Hutar, P.; Parsa Saeb, S.; Vanko, G.; Pribusova Slusna, L.; Ondič, Lukáš; Fait, Jan; Kromka, Alexander; Hulman, M.
2023 - English
Nowadays, 2D materials are one of the most studied classes of materials. In addition to the most famous graphene, progress has been achieved in studying and using fundamental properties of transition metal dichalcogenides (TMD). Complementary, diamond as a representative of 3D materials has gained a reputation as an extremely versatile material due to its extraordinary combination of physical/chemical/electrical/optical properties. Besides these particular forms of 2D and 3D materials, their heterostructures have become very attractive due to new phenomena and functions (bandgap engineering, enhanced charge transport, optical interaction, etc.). However, individual technological procedures are still minimally investigated and described. Here, we will demonstrate a proof-of-concept for the preparation of MoS2/diamond heterostructures, where two different strategies were employed: a) growth of MoS2 layers on diamond films, and b) growth of diamond films on Si/MoS2 substrates. Keywords: transition metal dichalcogenides; molybdenum disulfide; diamond; heterostructures Available at various institutes of the ASCR
Technological challenges in the fabrication of MoS.sub.2./sub./diamond heterostructures

Nowadays, 2D materials are one of the most studied classes of materials. In addition to the most famous graphene, progress has been achieved in studying and using fundamental properties of transition ...

Varga, Marián; Sojková, M.; Hrdá, J.; Hutar, P.; Parsa Saeb, S.; Vanko, G.; Pribusova Slusna, L.; Ondič, Lukáš; Fait, Jan; Kromka, Alexander; Hulman, M.
Fyzikální ústav, 2023

Enhanced growth rate of diamond films at low temperature in focused microwave plasma system
Babčenko, Oleg; Bydžovská, Irena; Fait, Jan; Shagieva, Ekaterina; Ondič, Lukáš; Kromka, Alexander
2023 - English
The low temperature (< 500 °C) diamond film deposition on fused silica in two different focused microwave plasma systems, i.e. a multimode clamshell cavity (MCC) and a rotational ellipsoid cavity (REC) reactor, was investigated. During the experiments, the methane to hydrogen ratio, in the hydrogen-rich process gas mixture, varied from 1 % to 15 % for MCC and from 1 % to 9 % for REC. The grown films were analyzed by scanning electron microscopy and Raman shift measurements. The outcomes of the study and enhanced diamond growth at low temperatures is advantageous for overcoating of fused silica as well as thermally sensitive substrates, e.g. optical elements, photonic crystals, sensors, etc. Keywords: well-faceted diamonds; low temperature deposition; high growth rate; low non-diamond content; focused plasma Available at various institutes of the ASCR
Enhanced growth rate of diamond films at low temperature in focused microwave plasma system

The low temperature (...

Babčenko, Oleg; Bydžovská, Irena; Fait, Jan; Shagieva, Ekaterina; Ondič, Lukáš; Kromka, Alexander
Fyzikální ústav, 2023

Termická analýza vstupních surovin pro růst krystalů vysokoteplotních komplexních oxidů
Zemenová, Petra; Král, Robert; Falvey, Alexandra; Pejchal, Jan; Bystřický, Aleš
2022 - Czech
Příspěvek se zabývá studiem tepelného chování oxidů vzácných zemin (La2O3, Sc2O3 a Gd2O3), které se používají jako výchozí suroviny při přípravě krystalů komplexních oxidů na bázi granátů a perovskitů, pomocí metod DSC-TG-MS. This contribution deals with the study of thermal behavior of oxide La2O3, Sc2O3 a Gd2O3 by methods DSC-TG-MS. Keywords: thermal analysis DSC-TG; mass spectrometry; oxide; high-temperature complex oxides crystals Available at various institutes of the ASCR
Termická analýza vstupních surovin pro růst krystalů vysokoteplotních komplexních oxidů

Příspěvek se zabývá studiem tepelného chování oxidů vzácných zemin (La2O3, Sc2O3 a Gd2O3), které se používají jako výchozí suroviny při přípravě krystalů komplexních oxidů na bázi granátů a ...

Zemenová, Petra; Král, Robert; Falvey, Alexandra; Pejchal, Jan; Bystřický, Aleš
Fyzikální ústav, 2022

Vliv velikosti zrn práškového NaCl na jeho termické vlastnosti
Falvey, Alexandra; Zemenová, Petra; Vaněček, Vojtěch; Bystřický, Aleš; Stehlík, Štěpán; Král, Robert
2022 - Czech
Příspěvek se zabývá studiem tepelného chování vzorku NaCl v práškové formě (s homogenní a nehomogenní distribucí zrn, různou vlhkostí) a monokrystalického NaCl metodami termické analýzy (DSC a TMA) a hmotnostní spektrometrii (MS). The paper deals with the study of the thermal behavior of a sample of NaCl in powder form (with homogeneous and inhomogeneous grain distribution, different humidity) and monocrystalline NaCl using the methods of thermal analysis (DSC and TMA) and mass spectrometry (MS). Keywords: thermal analysis Available at various institutes of the ASCR
Vliv velikosti zrn práškového NaCl na jeho termické vlastnosti

Příspěvek se zabývá studiem tepelného chování vzorku NaCl v práškové formě (s homogenní a nehomogenní distribucí zrn, různou vlhkostí) a monokrystalického NaCl metodami termické analýzy (DSC a TMA) a ...

Falvey, Alexandra; Zemenová, Petra; Vaněček, Vojtěch; Bystřický, Aleš; Stehlík, Štěpán; Král, Robert
Fyzikální ústav, 2022

Tenké vrstvy pro fotovoltaiku nanášené plasmochemickými metodami
Fejfar, Antonín
2022 - Czech
Tenké vrstvy jsou klíčovou komponentou prakticky všech moderních fotovoltaických článků pro využití sluneční energie. Články využívají tenké vrstvy pro dosažení optimálního záchytu světla, pro rozdělení a sběr fotogenerovaných nábojů i pro pasivaci rozhraní či přímo jako vrstvy absorbující fotony slunečního svitu. Každoročně jsou tak nanášeny vrstvy o celkové ploše řádu mnoha stovek kilometrů čtverečních, a to především s využitím plazmochemických technologií. Thin films are key components for practically all of contemporary photovoltaic cells for solar energy utilization. Cells use thin films for optimizing light trapping, for selecting and collection of photogenerated charges and interface passivation or as absorber layers. Each year several hundreds of square kilometers of thin films are deposited mainly by plasma chemistry methods. Keywords: thin films; deposition; plasma chemistry; photovoltaics Available at various institutes of the ASCR
Tenké vrstvy pro fotovoltaiku nanášené plasmochemickými metodami

Tenké vrstvy jsou klíčovou komponentou prakticky všech moderních fotovoltaických článků pro využití sluneční energie. Články využívají tenké vrstvy pro dosažení optimálního záchytu světla, pro ...

Fejfar, Antonín
Fyzikální ústav, 2022

Magnetocrystalline anisotropy of Ni-Mn-Ga-Co-Cu martensite
Rameš, Michal; Straka, Ladislav; Sozinov, A.; Heczko, Oleg
2022 - English
The martensites of Heusler alloys based on Ni-Mn-Ga exhibit magnetically-induced reorientation resulting in giant field-induced strain. Up to 12% strain was observed in Ni-Mn-Ga-Co-Cu with 4 at.% of Co and Cu. The driving force of the phenomenon is the magnetocrystalline anisotropy. We studied evolution of the anisotropy with temperature and compositions using magnetiyation curve measurements in four different single crystalline Ni-Mn-Ga-Co-Cu and compared with non-doped Ni-Mn-Ga. The anisotropy of martensite decreases with increasing average doping (Co+Cu)/2 but it does not scale with tetragonal ratio or valence electron concentration. Keywords: martensite; magnetocrystalline anisotropy; Heusler alloys; Ni-Mn-Ga Available at various institutes of the ASCR
Magnetocrystalline anisotropy of Ni-Mn-Ga-Co-Cu martensite

The martensites of Heusler alloys based on Ni-Mn-Ga exhibit magnetically-induced reorientation resulting in giant field-induced strain. Up to 12% strain was observed in Ni-Mn-Ga-Co-Cu with 4 at.% of ...

Rameš, Michal; Straka, Ladislav; Sozinov, A.; Heczko, Oleg
Fyzikální ústav, 2022

Chemická depozice diamantových tenkých vrstev z par plynů
Kromka, Alexander
2022 - Czech
Příprava diamantových vrstev a jejich (nano-) struktur vyžaduje zvládnutí více technologických kroků. V prvním kroku „diamantové technologie” je důležité aktivovat povrch nediamantové podložky vhodným procesem známým jako nukleace nebo zárodkování. Nejčastěji se jedná o proces pokrytí povrchu podložky (nano-) částicemi diamantu nebo aktivace povrchu podložky iontovým bombardováním. Druhým klíčovým krokem je samotný růst diamantové vrstvy tzv. chemickou depozicí z par plynů (tzv. „Chemical Vapor Deposition” - CVD) za nízkých tlaků (10 ÷ 10 000 Pa) a teplot v rozsahu 250 ÷ 1000 °C, která je nejčastěji realizována v plynné směsi metanu a vodíku v systému žhaveného vlákna nebo mikrovlnného plazmatu. V tomto příspěvku jsou oba technologické kroky, nukleace a růst, diskutovány se zřetelem aktuálních trendů a experimentálních aktivit probíhajících v laboratořích Fyzikálního ústavu AV ČR (FZÚ).\n The preparation of diamond layers and their (nano-) structures requires the optimization of several technological steps. In the first step of “diamond technology” it is important to activate the surface of the non-diamond substrate by a suitable process known as nucleation or nucleation. The second key step is the growth of the diamond layer itself by chemical vapor deposition (CVD) under low pressures (10 ÷ 10,000 Pa) and temperatures in the range of 250 ÷ 1000 °C, and from a gas mixture of methane and hydrogen commonly used in a hot filament or microwave plasma CVD systems. In this paper, both technological steps, nucleation and growth, are discussed in light of current trends and experimental activities taking place in the laboratories of the Institute of Physics of the Academy of Sciences of the Czech Republic (FZÚ). Keywords: diamond technology; nucleation; chemical vapor deposition Available at various institutes of the ASCR
Chemická depozice diamantových tenkých vrstev z par plynů

Příprava diamantových vrstev a jejich (nano-) struktur vyžaduje zvládnutí více technologických kroků. V prvním kroku „diamantové technologie” je důležité aktivovat povrch nediamantové podložky vhodným ...

Kromka, Alexander
Fyzikální ústav, 2022

Development and measurement of gas sensors for room temperature applications
Kočí, Michal
2022 - English
Gas sensing properties of a nanocrystalline diamond with a hydrogen-terminated surface (H-terminated NCD) and a molybdenum disulphide (MoS2) are investigated as conductivity sensors with built-in interdigital metal electrode structures. The H-terminated NCD was prepared by plasma-enhanced chemical vapour deposition (PECVD), and the MoS2 by a carbide-free one-zone sulfurization method. The sensor's responses were measured for oxidizing (NO2) and reducing (NH3) gases by the same equipment and setup. The parameters of the tested sensors are compared and critically evaluated. Advantageously, the MoS2/H-terminated NCD heterostructure enhances the gas sensing response at room temperature compared to the H-terminated NCD and MoS2 layers. Keywords: gas sensor; nanocrystalline diamond (NCD); transition metal dichalcogenide (TMD) Fulltext is available at external website.
Development and measurement of gas sensors for room temperature applications

Gas sensing properties of a nanocrystalline diamond with a hydrogen-terminated surface (H-terminated NCD) and a molybdenum disulphide (MoS2) are investigated as conductivity sensors with built-in ...

Kočí, Michal
Fyzikální ústav, 2022

Effect of molecular structure on liquid crystalline behaviour for chiral lactic acid derivatives
Mironov, Sergei; Bubnov, Alexej
2022 - English
Liquid crystals are self-organizing materials that have great potential for practical applications. The relationship has not been fully established and understood despite numerous studies. We discuss a relatively broad subclass of calamitic chiral lactic acid derivatives and provide specific examples of effective tuning of their mesomorphic and electro-optical behaviour using various types of lateral substitution placed on the molecular core. Keywords: chiral liquid crystals; lateral substitution; ferroelectric smectic phase; spontaneous polarization; lactic acid Available at various institutes of the ASCR
Effect of molecular structure on liquid crystalline behaviour for chiral lactic acid derivatives

Liquid crystals are self-organizing materials that have great potential for practical applications. The relationship ...

Mironov, Sergei; Bubnov, Alexej
Fyzikální ústav, 2022

About project

NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web

Send your suggestions and comments to nusl@techlib.cz

Provider

http://www.techlib.cz

Facebook

Other bases