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Shudong Xiao

Bio: Shudong Xiao is an academic researcher from University of Maryland, College Park. The author has contributed to research in topics: Physics & Solar wind. The author has an hindex of 9, co-authored 15 publications receiving 3316 citations. Previous affiliations of Shudong Xiao include Tsinghua University & Cornell University.

Papers
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Journal ArticleDOI
TL;DR: It is shown that electron-acoustic phonon scattering is indeed independent of n, and contributes only 30 Omega to graphene's room-temperature resistivity, and its magnitude, temperature dependence and carrier-density dependence are consistent with extrinsic scattering by surface phonons at the SiO2 substrate.
Abstract: The linear dispersion relation in graphene gives rise to a surprising prediction: the resistivity due to isotropic scatterers, such as white-noise disorder or phonons, is independent of carrier density, n. Here we show that electron-acoustic phonon scattering is indeed independent of n, and contributes only 30 Omega to graphene's room-temperature resistivity. At a technologically relevant carrier density of 1 x1012 cm-2, we infer a mean free path for electron-acoustic phonon scattering of >2 microm and an intrinsic mobility limit of 2 x 105 cm2 V-1 s-1. If realized, this mobility would exceed that of InSb, the inorganic semiconductor with the highest known mobility ( approximately 7.7 x 104 cm2 V-1 s-1; ref. 9) and that of semiconducting carbon nanotubes ( approximately 1 x 105 cm2 V-1 s-1; ref. 10). A strongly temperature-dependent resistivity contribution is observed above approximately 200 K (ref. 8); its magnitude, temperature dependence and carrier-density dependence are consistent with extrinsic scattering by surface phonons at the SiO2 substrate and limit the room-temperature mobility to approximately 4 x 104 cm2 V-1 s-1, indicating the importance of substrate choice for graphene devices.

2,947 citations

Journal ArticleDOI
TL;DR: The first demonstration of an important building block in vdW solids: room temperature Esaki tunnel diodes is presented and the broken-gap band alignment is confirmed by the junction photoresponse, and the phosphorus double planes in a single layer of BP are resolved in transmission electron microscopy (TEM) for the first time.
Abstract: van der Waals (vdW) heterojunctions composed of two-dimensional (2D) layered materials are emerging as a solid-state materials family that exhibits novel physics phenomena that can power a range of electronic and photonic applications. Here, we present the first demonstration of an important building block in vdW solids: room temperature Esaki tunnel diodes. The Esaki diodes were realized in vdW heterostructures made of black phosphorus (BP) and tin diselenide (SnSe2), two layered semiconductors that possess a broken-gap energy band offset. The presence of a thin insulating barrier between BP and SnSe2 enabled the observation of a prominent negative differential resistance (NDR) region in the forward-bias current–voltage characteristics, with a peak to valley ratio of 1.8 at 300 K and 2.8 at 80 K. A weak temperature dependence of the NDR indicates electron tunneling being the dominant transport mechanism, and a theoretical model shows excellent agreement with the experimental results. Furthermore, the bro...

304 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of the corrugations (ripples) of graphene on SiO2 on transport were evaluated by measuring the height-height correlation function, and it was shown that the Corrugations cannot mimic long-range (charged impurity) scattering effects, and have too small an amplitude-to-wavelength ratio to significantly affect the observed mobility via short-range scattering.

107 citations

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TL;DR: In this paper, the impact of charged impurity scattering on charge carrier transport in bilayer graphene (BLG) by deposition of potassium in ultrahigh vacuum at low temperature was examined.
Abstract: We have examined the impact of charged impurity scattering on charge carrier transport in bilayer graphene (BLG) by deposition of potassium in ultrahigh vacuum at low temperature. Charged impurity scattering gives a conductivity which is supralinear in carrier density with a magnitude similar to single-layer graphene for the measured range of carrier densities of $2--4\ifmmode\times\else\texttimes\fi{}{10}^{12}\text{ }{\text{cm}}^{\ensuremath{-}2}$. Upon addition of charged impurities of concentration ${n}_{\text{imp}}$, the minimum conductivity ${\ensuremath{\sigma}}_{\text{min}}$ decreases proportional to ${n}_{\text{imp}}^{\ensuremath{-}1/2}$ while the electron and hole puddle carrier density increases proportional to ${n}_{\text{imp}}^{1/2}$. These results for the intentional deposition of potassium on BLG are consistent with theoretical predictions for charged impurity scattering assuming a gapless hyperbolic dispersion relation. However, our results also suggest that charged impurity scattering alone cannot explain the observed transport properties of pristine BLG on ${\text{SiO}}_{2}$ before potassium doping.

70 citations


Cited by
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TL;DR: This work reviews the historical development of Transition metal dichalcogenides, methods for preparing atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics.
Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

13,348 citations

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TL;DR: An overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them), from a materials science perspective.
Abstract: There is intense interest in graphene in fields such as physics, chemistry, and materials science, among others. Interest in graphene's exceptional physical properties, chemical tunability, and potential for applications has generated thousands of publications and an accelerating pace of research, making review of such research timely. Here is an overview of the synthesis, properties, and applications of graphene and related materials (primarily, graphite oxide and its colloidal suspensions and materials made from them), from a materials science perspective.

8,919 citations

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TL;DR: In this paper, a single layer graphene was suspended ∼150nm above a Si/SiO2 gate electrode and electrical contacts to the graphene was achieved by a combination of electron beam lithography and etching.

7,276 citations

Journal ArticleDOI
TL;DR: In this article, a few-layer black phosphorus crystals with thickness down to a few nanometres are used to construct field effect transistors for nanoelectronic devices. But the performance of these materials is limited.
Abstract: Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Experimentally identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, we fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometres. Reliable transistor performance is achieved at room temperature in samples thinner than 7.5 nm, with drain current modulation on the order of 10(5) and well-developed current saturation in the I-V characteristics. The charge-carrier mobility is found to be thickness-dependent, with the highest values up to ∼ 1,000 cm(2) V(-1) s(-1) obtained for a thickness of ∼ 10 nm. Our results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices.

6,924 citations