scholarly journals Интеркалирование графена на карбиде кремния кобальтом

2019 ◽  
Vol 61 (7) ◽  
pp. 1374
Author(s):  
Г.С. Гребенюк ◽  
Е.Ю. Лобанова ◽  
Д.А. Смирнов ◽  
И.А. Елисеев ◽  
А.В. Зубов ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Single Layer ◽  
High Energy ◽  
Single Layer Graphene ◽  
High Energy Resolution ◽  
Cobalt Films ◽  
Cobalt Silicides

AbstractIn this paper, we studied cobalt intercalation of single-layer graphene grown on the 4 H -SiC(0001) polytype. The experiments were carried out in situ under ultrahigh vacuum conditions by high energy resolution photoelectron spectroscopy using synchrotron radiation and low energy electron diffraction. The nominal thicknesses of the deposited cobalt layers varied in the range of 0.2–5 nm, while the sample temperature was varied from room temperature to 800°C. Unlike Fe films, the annealing of Co films deposited on graphene at room temperature is shown to not intercalate graphene by cobalt. The formation of the graphene–cobalt–SiC intercalation system was detected upon deposition of Co atoms on samples heated to temperatures of above ~400°C. Cobalt films with a thickness up to 2 nm under graphene are formed using this method, and they are shown to be magnetized along the surface at thicknesses of greater than 1.3 nm. Graphene intercalation by cobalt was found to be accompanied by the chemical interaction of Co atoms with silicon carbide leading to the synthesis of cobalt silicides. At temperatures of above 500°C, the growth of cobalt films under graphene is limited by the diffusion of Co atoms into the bulk of silicon carbide.

scholarly journals Интеркаляционный синтез силицидов кобальта под графеном, выращенным на карбиде кремния

2020 ◽  
Vol 62 (3) ◽  
pp. 462
Author(s):  
Г.С. Гребенюк ◽  
И.А. Елисеев ◽  
С.П. Лебедев ◽  
Е.Ю. Лобанова ◽  
Д.А. Смирнов ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Photoelectron Spectroscopy ◽  
Single Layer ◽  
High Energy ◽  
Single Layer Graphene ◽  
High Energy Resolution ◽  
Kelvin Probe ◽  
Layer Graphene ◽  
Atomic Force ◽  
Cobalt Silicides

Abstract The process of formation of cobalt silicides near the graphene-silicon carbide interface by intercalation of single-layer graphene grown on the 4 H - and 6 H -SiC(0001) polytypes with cobalt and silicon is studied. The experiments were carried out in situ in ultrahigh vacuum. The analysis of the samples is performed by high-energy-resolution photoelectron spectroscopy using synchrotron radiation, low-energy electron diffraction, and also Raman spectroscopy, atomic-force and kelvin-probe microscopies. The thicknesses of the deposited cobalt and silicon layers is varied to 2 nm, and the sample temperature, from room temperature to 1000°C. Co and Si atoms deposited on heated samples is found to penetrate under graphene and are localized between the buffer layer and the substrate, which leads to a transformation of the buffer layer into additional graphene layer. It is shown that the result of intercalation of the system with cobalt and silicon is the formation under two-layer graphene of a Co–Si solid solution and silicide CoSi coated by the surface Co_3Si phase. It is shown that the thickness and the composition of the formed silicide films can be changed by varying the amount of the intercalated material and the order of their depositions.

scholarly journals Интеркалирование графена, сформированного на карбиде кремния, атомами железа

2018 ◽  
Vol 60 (7) ◽  
pp. 1423
Author(s):  
М.В. Гомоюнова ◽  
Г.С. Гребенюк ◽  
В.Ю. Давыдов ◽  
И.А. Ермаков ◽  
И.А. Елисеев ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Photoelectron Spectroscopy ◽  
Chemical Interaction ◽  
High Energy ◽  
High Energy Resolution ◽  
Iron Film ◽  
Graphene Monolayer ◽  
X Ray Absorption ◽  
Layer Coating

AbstractThe intercalation of iron under a graphene monolayer grown on 4 H -SiC(0001) is studied. The experiments have been carried out in situ under conditions of ultrahigh vacuum by low-energy electron diffraction, high-energy-resolution photoelectron spectroscopy using synchrotron radiation, and near carbon K -edge X-ray absorption spectroscopy. The deposited iron film thicknesses have been varied within 0.1–2 nm and the sample temperatures from room temperature to 700°C. It is shown that the intercalation process begins at temperatures higher than ~350°C. In this case, it is found that intercalated iron atoms are localized not only between graphene and a buffer layer coating SiC, but also under the buffer layer itself. The optimal conditions of the intercalation are realized in the range 400–500°C, because, at higher temperatures, the system becomes unstable due to the chemical interaction of the intercalated iron with silicon carbide. The inertness of the intercalated films to action of oxygen is demonstrated.

scholarly journals Comparison between Silicon-Carbide and diamond for fast neutron detection at room temperature

2018 ◽  
Vol 170 ◽  
pp. 08006 ◽  
Author(s):  
O. Obraztsova ◽  
L. Ottaviani ◽  
A. Klix ◽  
T. Döring ◽  
O. Palais ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
High Temperature ◽  
Band Gap ◽  
Room Temperature ◽  
Radiation Detection ◽  
Neutron Detection ◽  
High Energy ◽  
High Energy Resolution ◽  
Fast Neutrons

Neutron radiation detector for nuclear reactor applications plays an important role in getting information about the actual neutron yield and reactor environment. Such detector must be able to operate at high temperature (up to 600° C) and high neutron flux levels. It is worth nothing that a detector for industrial environment applications must have fast and stable response over considerable long period of use as well as high energy resolution. Silicon Carbide is one of the most attractive materials for neutron detection. Thanks to its outstanding properties, such as high displacement threshold energy (20-35 eV), wide band gap energy (3.27 eV) and high thermal conductivity (4.9 W/cm·K), SiC can operate in harsh environment (high temperature, high pressure and high radiation level) without additional cooling system. Our previous analyses reveal that SiC detectors, under irradiation and at elevated temperature, respond to neutrons showing consistent counting rates as function of external reverse bias voltages and radiation intensity. The counting-rate of the thermal neutron-induced peak increases with the area of the detector, and appears to be linear with respect to the reactor power. Diamond is another semi-conductor considered as one of most promising materials for radiation detection. Diamond possesses several advantages in comparison to other semiconductors such as a wider band gap (5.5 eV), higher threshold displacement energy (40-50 eV) and thermal conductivity (22 W/cm·K), which leads to low leakage current values and make it more radiation resistant that its competitors. A comparison is proposed between these two semiconductors for the ability and efficiency to detect fast neutrons. For this purpose the deuterium-tritium neutron generator of Technical University of Dresden with 14 MeV neutron output of 1010 n·s-1 is used. In the present work, we interpret the first measurements and results with both 4H-SiC and chemical vapor deposition (CVD) diamond detectors irradiated with 14 MeV neutrons at room temperature.

scholarly journals Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Increasing Trend ◽  
Substrate Temperatures ◽  
Beam Technique

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.

Silicon Carbide for Alpha, Beta, Ion and Soft X-Ray High Performance Detectors

2005 ◽  
Vol 483-485 ◽  
pp. 1015-1020 ◽  
Author(s):  
Giuseppe Bertuccio ◽  
Simona Binetti ◽  
S. Caccia ◽  
R. Casiraghi ◽  
Antonio Castaldini ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Collection Efficiency ◽  
High Energy ◽  
Beta Particle ◽  
High Energy Resolution ◽  
Charge Collection Efficiency ◽  
X Ray ◽  
Current Densities ◽  
Full Charge

High performance SiC detectors for ionising radiation have been designed, manufactured and tested. Schottky junctions on low-doped epitaxial 4H-SiC with leakage current densities of few pA/cm2 at room temperature has been realised at this purpose. The epitaxial layer has been characterised at different dose of radiations in order to investigate the SiC radiation hardness. The response of the detectors to alpha and beta particle and to soft X-ray have been measured. High energy resolution and full charge collection efficiency have been successfully demonstrated.

Electrochemical Epitaxial (200) PbSe submicron-plates on Single-Layer Graphene for Ultrafast Infrared Response

2021 ◽  
Author(s):  
Chan Yang ◽  
Shuanglong Feng ◽  
Yinye Yu ◽  
Jun Shen ◽  
Xingzhan Wei ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Layer ◽  
Infrared Detection ◽  
Single Layer Graphene ◽  
Robust Detection ◽  
Layer Graphene ◽  
Highly Efficient ◽  
Low Visibility ◽  
Ultrafast Infrared

Highly efficient near and medium-wave infrared detection at room temperature is considered one of the most intensive studies due to their robust detection in foggy weather or other low visibility...

Epitaxial Single-Layer Graphene on the SiC Substrate

2012 ◽  
Vol 717-720 ◽  
pp. 645-648 ◽  
Author(s):  
Sergey Yu. Davydov ◽  
Alexander A. Lebedev
Keyword(s):  
Silicon Carbide ◽  
Density Of States ◽  
Anderson Model ◽  
Single Layer ◽  
Epitaxial Graphene ◽  
Single Layer Graphene ◽  
Electron Charge ◽  
Analytical Expression ◽  
Layer Graphene

The analytical expression for the density-of-states (DOS) of single-layer graphene interacting with the SiC surface (epitaxial graphene) is obtained. The silicon carbide DOS is described within the scope of the Haldane-Anderson model. It is shown that due to the interaction with the substrate the gap of about 0.01-0.06 eV arises in the epitaxial graphene DOS. The estimation indicates that the electron charge of about (−10-3) e/atom transfers from the substrate to graphene.

scholarly journals Graphene on SiC(0001) inspected by dynamic atomic force microscopy at room temperature

2015 ◽  
Vol 6 ◽  
pp. 901-906 ◽  
Author(s):  
Mykola Telychko ◽  
Jan Berger ◽  
Zsolt Majzik ◽  
Pavel Jelínek ◽  
Martin Švec
Keyword(s):  
Electron Scattering ◽  
Room Temperature ◽  
Single Layer ◽  
Tunneling Current ◽  
Single Layer Graphene ◽  
Force Microscopy ◽  
Atomic Force ◽  
Scattering Effects ◽  
Out Of Plane ◽  
Theoretical Simulations

We investigated single-layer graphene on SiC(0001) by atomic force and tunneling current microscopy, to separate the topographic and electronic contributions from the overall landscape. The analysis revealed that the roughness evaluated from the atomic force maps is very low, in accord with theoretical simulations. We also observed that characteristic electron scattering effects on graphene edges and defects are not accompanied by any out-of-plane relaxations of carbon atoms.

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