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 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.

Structural Strain in Single Layer Graphene Fabricated on SiC

2019 ◽  
Vol 963 ◽  
pp. 161-165
Author(s):  
Wan Cheng Yu ◽  
Xiu Fang Chen ◽  
Xiao Bo Hu ◽  
Xian Gang Xu ◽  
Peng Jin ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Single Layer ◽  
Ex Situ ◽  
Single Layer Graphene ◽  
Growth Time ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force ◽  
Structural Strain

Single layer graphene is fabricated on the Si face of silicon carbide through thermal decomposition. The thickness of graphene was checked by a combination of ex situ Kelvin probe force microscopy together with Raman spectroscopy and atomic force microscopy. The amount of residual strain induced is calculated to between 1.3% and 0.7%. Results also show that the magnitude of strain increased with growth time while the uniformity of strain improved.

scholarly journals Routes to rupture and folding of graphene on rough 6H-SiC(0001) and their identification

2013 ◽  
Vol 4 ◽  
pp. 625-631 ◽  
Author(s):  
M Temmen ◽  
O Ochedowski ◽  
B Kleine Bussmann ◽  
M Schleberger ◽  
M Reichling ◽  
...  
Keyword(s):  
Contact Potential Difference ◽  
Single Layer ◽  
Heavy Ion ◽  
Single Layer Graphene ◽  
Ambient Conditions ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Shi Irradiation

Twisted few layer graphene (FLG) is highly attractive from an application point of view, due to its extraordinary electronic properties. In order to study its properties, we demonstrate and discuss three different routes to in situ create and identify (twisted) FLG. Single layer graphene (SLG) sheets mechanically exfoliated under ambient conditions on 6H-SiC(0001) are modified by (i) swift heavy ion (SHI) irradiation, (ii) by a force microscope tip and (iii) by severe heating. The resulting surface topography and the surface potential are investigated with non-contact atomic force microscopy (NC-AFM) and Kelvin probe force microscopy (KPFM). SHI irradiation results in rupture of the SLG sheets, thereby creating foldings and bilayer graphene (BLG). Applying the other modification methods creates enlarged (twisted) graphene foldings that show rupture along preferential edges of zigzag and armchair type. Peeling at a folding over an edge different from a low index crystallographic direction can result in twisted BLG, showing a similar height as Bernal (or AA-stacked) BLG in NC-AFM images. The rotational stacking can be identified by a significant contrast in the local contact potential difference (LCPD) measured by KPFM.

High-energy collective electronic excitations in free-standing single-layer graphene

2013 ◽  
Vol 88 (7) ◽  
Author(s):  
P. Wachsmuth ◽  
R. Hambach ◽  
M. K. Kinyanjui ◽  
M. Guzzo ◽  
G. Benner ◽  
...  
Keyword(s):  
Single Layer ◽  
High Energy ◽  
Single Layer Graphene ◽  
Electronic Excitations ◽  
Free Standing ◽  
Layer Graphene

scholarly journals Incorporation of Boron Atoms on Graphene Grown by Chemical Vapor Deposition Using Triisopropyl Borate as a Single Precursor

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
E. C. Romani ◽  
D. G. Larrude ◽  
M. E. H. Maia da Costa ◽  
G. Mariotto ◽  
F. L. Freire
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Layer Graphene ◽  
Pristine Graphene ◽  
Processing Temperature ◽  
Xps Spectra ◽  
Layer Graphene

We synthesized single-layer graphene from a liquid precursor (triisopropyl borate) using a chemical vapor deposition. Optical microscopy, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy measurements were used for the characterization of the samples. We investigated the effects of the processing temperature and time, as well as the vapor pressure of the precursor. The B1s core-level XPS spectra revealed the presence of boron atoms incorporated into substitutional sites. This result, corroborated by the observed upshift of both G and 2D bands in the Raman spectra, suggests the p-doping of single-layer graphene for the samples prepared at 1000°C and pressures in the range of 75 to 25 mTorr of the precursor vapor. Our results show that, in optimum conditions for single-layer graphene growth, that is, 1000°C and 75 mTorr for 5 minutes, we obtained samples presenting the coexistence of pristine graphene with regions of boron-doped graphene.

scholarly journals Configurational Effects on Strain and Doping at Graphene-Silver Nanowire Interfaces

2020 ◽  
Vol 10 (15) ◽  
pp. 5157
Author(s):  
Frank Lee ◽  
Manoj Tripathi ◽  
Peter Lynch ◽  
Alan B. Dalton
Keyword(s):  
Atomic Force Microscopy ◽  
Adhesion Force ◽  
Single Layer ◽  
Silver Nanowire ◽  
Single Layer Graphene ◽  
Fermi Energy Level ◽  
Essential Information ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force

Graphene shows substrate-dependent physical and electronic properties. Here, we presented the interaction between single-layer graphene and silver nanowire (AgNW) in terms of physical straining and doping. We observed a snap-through event for single-layer graphene/AgNW at a separation of AgNWs of 55 nm, beyond the graphene suspended over the nanowires. The adhesion force between the Atomic Force Microscopy (AFM) tip apex and the suspended graphene was measured as higher than the conformed one by 1.8 nN. The presence of AgNW modulates the Fermi energy level of graphene and reduces the work function by 0.25 eV, which results in n-type doping. Consequently, a lateral p-n-p junction is formed with single AgNW. The correlation Raman plot between G-2D modes reveals the increment of strain in graphene of 0.05% due to the curvature around AgNW, and 0.01% when AgNW lies on the top of graphene. These results provide essential information in inspecting the physical and electronic influences from AgNW.

Nanolithography of Single-Layer Graphene Oxide Films by Atomic Force Microscopy

Langmuir ◽  
2010 ◽  
Vol 26 (9) ◽  
pp. 6164-6166 ◽  
Author(s):  
Gang Lu ◽  
Xiaozhu Zhou ◽  
Hai Li ◽  
Zongyou Yin ◽  
Bing Li ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Oxide Films ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Force Microscopy ◽  
Layer Graphene ◽  
Atomic Force
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