The impact of partial H intercalation on the quasi-free-standing properties of graphene on SiC(0001)

Szary, Maciej J.; El-Ahmar, Semir; Ciuk, Tymoteusz

doi:10.1016/j.apsusc.2020.148668

Cited by 14 publications

(4 citation statements)

References 49 publications

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“…One of the methods for separating graphene sheets from a substrate is hydrogen intercalation, which creates quasi-free layers on the SiC (0001) surface [16]. The quantum Hall resistance is consistent with the nominal value (half of the Klitzing background constant) within a standard deviation of 4.5 × 10 −9 , which makes this method suitable for the manufacture of electrical quantum standards.…”

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confidence: 68%

Recent Advances in Graphene Epitaxial Growth: Aspects of Substrate Surface Modification Using Coatings

Ramazanov

2022

Coatings

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confidence: 68%

Recent Advances in Graphene Epitaxial Growth: Aspects of Substrate Surface Modification Using Coatings

Ramazanov

2022

Coatings

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“…The hydrogen-intercalated QFS graphene , (branded GET) was grown at 1600 °C on a semi-insulating vanadium-compensated nominally on-axis 15 mm × 15 mm 6H-SiC(0001) substrate (II–VI Inc.) through epitaxial CVD in the hot-wall Epigress VP508 reactor with propane as a carbon source . The in situ intercalation with hydrogen atoms took place at 1000 °C in a 900 mbar argon atmosphere.…”

Section: Methodsmentioning

confidence: 99%

“…Of particular scientific and applied interest is transfer-free p-type hydrogen-intercalated − quasi-free-standing (QFS) epitaxial chemical vapor deposition (CVD) graphene grown on semi-insulating, nominally on-axis, hexagonal SiC(0001) and passivated with a thin layer of amorphous atomic-layer deposition (ALD) aluminum oxide (a-Al 2 O 3 ), as its charge carrier type and sheet density is influenced by two contradictory charge induction mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Origin of the Double Polarization Mechanism in Aluminum-Oxide-passivated Quasi-free-standing Epitaxial Graphene on 6H-SiC(0001)

Piętak-Jurczak,

Gaca,

Dobrowolski

et al. 2024

ACS Appl. Electron. Mater.

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In this work, we synthesize a 43 nm thick layer of amorphous Al 2 O 3 on transfer-free p-type hydrogen-intercalated quasi-free-standing (QFS) epitaxial chemical vapor deposition graphene on semi-insulating vanadium-compensated on-axis 6H-SiC(0001), using trimethylaluminum as the source of aluminum and deionized water or oxygen plasma as the source of oxygen. With a combination of surface-sensitive X-ray reflectometry (angular range of 0−6°), spectroscopic ellipsometry (angle of incidence of 49°and λ = 490 nm), and scanning transmission electron microscopy combined with energy-dispersive X-ray spectroscopy, we draw depth profiles of the physical density, refractive index, and elemental composition to reveal that the physical properties of the oxide are inhomogeneous. Its density increases from the graphene interface (ρ = ∼1.5 g/cm 3 ) toward the surface (ρ = ∼3.0 g/cm 3 ). Characteristically, it takes 26 nm for the oxide density to equal its reference value on a test silicon substrate. We demonstrate that an additional postdeposition annealing step in an oxygen-radical-reach environment densifies the oxide and elevates its oxygen content, thus suggesting that the a-Al 2 O 3 is oxygen deficient. We reason that the structural inhomogeneity induces the negative polarization effect and the associated reduction of intrinsic hole density observed in a-Al 2 O 3passivated p-type QFS graphene on hexagonal SiC(0001).

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“…QFS graphene [ 26 , 27 , 28 , 29 ] necessary for the graphene-based HTHS was grown on semi-insulating high-purity on-axis 4H-SiC(0001) (Cree Inc.) in a hot-wall Aixtron VP508 reactor using the epitaxial Chemical Vapor Deposition method [ 30 ], with thermally decomposed propane as a carbon source and in situ hydrogen atom intercalation [ 31 ]. The substrate was processed into a 1.6 mm × 1.6 mm Hall effect structure featuring a cross-shaped [ 32 ] 100

m × 300

m graphene mesa and four Ti/Au (10 nm / 60 nm) ohmic contacts, all passivated with a 100 nm-thick aluminum oxide (Al 2 O 3 ) layer synthesized from trimethylaluminum (TMA) and deionized water at 670 K in a Picosun R200 Advanced Atomic Layer Deposition (ALD) reactor [ 33 , 34 ].…”

Section: Methodsmentioning

confidence: 99%

The Comparison of InSb-Based Thin Films and Graphene on SiC for Magnetic Diagnostics under Extreme Conditions

El-Ahmar

Przychodnia

Jankowski

et al. 2022

Sensors

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The ability to precisely measure magnetic fields under extreme operating conditions is becoming increasingly important as a result of the advent of modern diagnostics for future magnetic-confinement fusion devices. These conditions are recognized as strong neutron radiation and high temperatures (up to 350 °C). We report on the first experimental comparison of the impact of neutron radiation on graphene and indium antimonide thin films. For this purpose, a 2D-material-based structure was fabricated in the form of hydrogen-intercalated quasi-free-standing graphene on semi-insulating high-purity on-axis 4H-SiC(0001), passivated with an Al2O3 layer. InSb-based thin films, donor doped to varying degrees, were deposited on a monocrystalline gallium arsenide or a polycrystalline ceramic substrate. The thin films were covered with a SiO2 insulating layer. All samples were exposed to a fast-neutron fluence of ≈7×1017 cm−2. The results have shown that the graphene sheet is only moderately affected by neutron radiation compared to the InSb-based structures. The low structural damage allowed the graphene/SiC system to retain its electrical properties and excellent sensitivity to magnetic fields. However, InSb-based structures proved to have significantly more post-irradiation self-healing capabilities when subject to proper temperature treatment. This property has been tested depending on the doping level and type of the substrate.

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The impact of partial H intercalation on the quasi-free-standing properties of graphene on SiC(0001)

Cited by 14 publications

References 49 publications

Recent Advances in Graphene Epitaxial Growth: Aspects of Substrate Surface Modification Using Coatings

Recent Advances in Graphene Epitaxial Growth: Aspects of Substrate Surface Modification Using Coatings

Origin of the Double Polarization Mechanism in Aluminum-Oxide-passivated Quasi-free-standing Epitaxial Graphene on 6H-SiC(0001)

The Comparison of InSb-Based Thin Films and Graphene on SiC for Magnetic Diagnostics under Extreme Conditions

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