Ballistic Transport Exceeding 28 μm in CVD Grown Graphene

Banszerus, Luca; Schmitz, M.; Engels, Stephan; Goldsche, Matthias; Watanabe, Kenji; Taniguchi, Takashi; Beschoten, Bernd; Stampfer, Christoph

doi:10.1021/acs.nanolett.5b04840

Cited by 280 publications

(299 citation statements)

References 31 publications

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“…This was clearly demonstrated by the use of hexagonal boron nitride (h-BN) as a substrate material and gate dielectric [79], which can lead to very high mobilities in both single-crystal and bilayer graphene [80,81]. In cases where the surface of graphene is not exposed to any organic compounds during the transfer process, the mobility is also greatly improved [82] although in this case perhaps the benefit is also associated with low strain in the graphene films transferred using h-BN [83].…”

Section: Global Transport Properties Of Polycrystalline Graphenementioning

confidence: 99%

Scaling properties of polycrystalline graphene: a review

et al. 2016

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We present an overview of the electrical, mechanical, and thermal properties of polycrystalline graphene. Most global properties of this material, such as the charge mobility, thermal conductivity, or Young's modulus, are sensitive to its microstructure, for instance the grain size and the presence of line or point defects. Both the local and global features of polycrystalline graphene have been investigated by a variety of simulations and experimental measurements. In this review, we summarize the properties of polycrystalline graphene, and by establishing a perspective on how the microstructure impacts its large-scale physical properties, we aim to provide guidance for further optimization and improvement of applications based on this material, such as flexible and wearable electronics, and high-frequency or spintronic devices.

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Section: Global Transport Properties Of Polycrystalline Graphenementioning

confidence: 99%

Scaling properties of polycrystalline graphene: a review

et al. 2016

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“…Few-layer graphene can be prepared by the layer-by-layer stacking of monolayer graphene or by direct growth, and less than 4 layers is generally acceptable considering the typical requirement of >85% transmittance. Even though the electrical quality of CVDgrown graphene encapsulated in hexagonal boron nitride supports ballistic transport over distance larger than 28 μm at a low temperature, [101] the transfer process generally leads to structural damage and distortion, such as wrinkles, cracks and open edges, thus degrading the electrical performance of graphene TCFs. The transfer of 30-inch graphene films from flexible copper foils to PET substrates has been achieved through a R2R transfer method, as shown in Figure 2a.…”

Section: Graphene Transparent Conductive Filmsmentioning

confidence: 99%

All‐Carbon Thin‐Film Transistors as a Step Towards Flexible and Transparent Electronics

Sun

Liu

Ren

et al. 2016

Adv Elect Materials

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silicon wafer, TFTs can be fabricated on various types of rigid or flexible substrates. [1] TFTs fabricated on glass are primarily used for driving circuits in the liquid-crystal displays of televisions, computer monitors, and mobile phones, etc. Well-established TFT technologies based on amorphous silicon and polycrystalline silicon are well-suited for large-area, highresolution panels, e.g., six pieces of 65-and 75-inch TFT arrays can be fabricated on a 10.5th generation glass substrate. [2] However, TFTs based on these silicon-based semiconductors still face challenges in flexible and transparent applications, which would allow circuit integration on curved and non-rigid surfaces and in multi-layer packaging, e.g., head-up displays on windshields, informational displays on eyeglasses and transparent electronic skin in wearable electronics. [3] In terms of the materials used to construct flexible and transparent devices, not only the transistor channel but also the dielectric layers and metallic interconnects should have excellent flexibility and transparency. [4] The following factors play critical roles in the selection of channel materials: carrier mobility, temperature of material preparation, flexibility, large area availability, cost and stability. Carrier mobility is an important parameter to characterize the drift velocity of electrons or holes in a semiconductor under an applied electric field. [5] A high mobility corresponds to a high operating speed of the TFTs and their circuits. The only advantage of low-temperature polycrystalline silicon is its relatively high mobility. [6] Amorphous oxide semiconductors, including indium gallium zinc oxide, have a modest mobility and are costly due to the use of noble metal elements. [7] Hydrogenterminated amorphous silicon has modest properties in carrier mobility, large-area and flexibility, [1] and organic semiconductors are better suited for flexible and transparent TFTs except for their shortcomings of low mobility and poor environmental stability. [8] On the other hand, normal metal electrodes, such as gold, silver, aluminum and copper, cannot be used to form transparent electrodes due to their poor light transmittance. Both transparent indium tin oxide (ITO) electrodes and opaque metal electrodes suffer from flexibility constraints and can usually tolerate strains of less than 2%. [9][10][11] Therefore, the discovery of new types of robust channel and electrode materials is essential to achieve transparent, flexible, and even stretchable electronics. [12] Carbon nanomaterials, such as carbon nanotubes (CNTs) and graphene, have attracted great attention for potential use in flexible and transparent electronics since their discovery in the last two decades, [13,14] owing to their excellent properties Carbon nanotubes and graphene have attracted great attention for potential applications in flexible and transparent electronics, owing to their exceptional properties including very high electrical conductivity, optical transmittance, mechanical strength and f...

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“…Currently, there is a great deal of interest in layered heterostructures of these materials [3,4], where the combined system might be engineered for specific applications [5] or might enable the exploration of new phenomena [6,7]. In the field of spintronics, graphene has exceptional charge transport properties but weak spin-orbit coupling (SOC) on the order of 10 µeV [8], which makes it ideal for long-distance spin transport [9][10][11] but ineffective for generating or manipulating spin currents. To advance towards spin manipulation, recent work has focused on heterostructures of graphene and magnetic insulators [12][13][14][15][16] or strong SOC materials such as transition metal dichalcogenides (TMDCs) and topological insulators [17][18][19].…”

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confidence: 99%

Giant Spin Lifetime Anisotropy in Graphene Induced by Proximity Effects

et al. 2017

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We report on fundamental aspects of spin dynamics in heterostructures of graphene and transition metal dichalcogenides (TMDCs). By using realistic models derived from first principles we compute the spin lifetime anisotropy, defined as the ratio of lifetimes for spins pointing out of the graphene plane to those pointing in the plane. We find that the anisotropy can reach values of tens to hundreds, which is unprecedented for typical 2D systems with spin-orbit coupling and indicates a qualitatively new regime of spin relaxation. This behavior is mediated by spin-valley locking, which is strongly imprinted onto graphene by TMDCs. Our results indicate that this giant spin lifetime anisotropy can serve as an experimental signature of materials with strong spin-valley locking, including graphene/TMDC heterostructures and TMDCs themselves. Additionally, materials with giant spin lifetime anisotropy can provide an exciting platform for manipulating the valley and spin degrees of freedom, and for designing novel spintronic devices. [3,4], where the combined system might be engineered for specific applications [5] or might enable the exploration of new phenomena [6,7]. In the field of spintronics, graphene has exceptional charge transport properties but weak spin-orbit coupling (SOC) on the order of 10 µeV [8], which makes it ideal for long-distance spin transport [9-11] but ineffective for generating or manipulating spin currents. To advance towards spin manipulation, recent work has focused on heterostructures of graphene and magnetic insulators [12][13][14][15][16] or strong SOC materials such as transition metal dichalcogenides (TMDCs) and topological insulators [17][18][19]. The SOC induced in graphene by a TMDC could enable phenomena such as topological edge states [20] or the spin Hall effect [21][22][23].To this end, a variety of recent experiments have explored spin transport in graphene/TMDC heterostructures [21,[24][25][26][27][28][29]. Magnetotransport measurements revealed that graphene in contact with WS 2 exhibits a large weak antilocalization (WAL) peak, revealing a strong SOC induced by proximity effects [24][25][26]30]. Fits to the magnetoconductance yielded spin lifetimes τ s ≈ 5 ps, which is two to three orders of magnitude lower than graphene on traditional substrates [10,31]. It was later asserted that after the removal of a temperatureindependent background, τ s becomes at most only a few hundred femtoseconds [26]. Nonlocal Hanle measurements, meanwhile, have revealed spin lifetimes up to a few tens of picoseconds [27][28][29] that can be tuned by a back gate [28,29]. Finally, charge transport measure-

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Ballistic Transport Exceeding 28 μm in CVD Grown Graphene

Cited by 280 publications

References 31 publications

Scaling properties of polycrystalline graphene: a review

Scaling properties of polycrystalline graphene: a review

All‐Carbon Thin‐Film Transistors as a Step Towards Flexible and Transparent Electronics

Giant Spin Lifetime Anisotropy in Graphene Induced by Proximity Effects

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