Showing papers by "Helin Cao published in 2013"
TL;DR: In this paper, the authors present the results of an experiment at the Princeton Institute for Science and Technology of Materials (Princeton Institute for Materials, Princeton University, 70 Prospect Ave., Princeton, NJ 08544, USA 5 School of Electrical and Computer Engineering, Purdue University, 465 Northwestern Ave., West Lafayette, IN 47907 USA
Abstract: 1 Department of Physics, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, USA 2 Birck Nanotechnology Center, Purdue University, 1205 W. State St., West Lafayette, IN 47907, USA 3 Joseph Henry Laboratories, Department of Physics, Princeton University, Jadwin Hall, Princeton, NJ 08544, USA 4 Princeton Institute for Science and Technology of Materials, Princeton University, 70 Prospect Ave., Princeton, NJ 08544, USA 5 School of Electrical and Computer Engineering, Purdue University, 465 Northwestern Ave., West Lafayette, IN 47907 USA
46 citations
TL;DR: In this paper, the synthesis and characterizations of synthetic graphene grown on copper foil substrates by atmospheric pressure chemical vapour deposition is discussed. And the potential applications of such large scale synthetic graphene are discussed.
Abstract: The discovery of graphene, a single layer of covalently bonded carbon atoms, has attracted intense interests. Initial studies using mechanically exfoliated graphene unveiled its remarkable electronic, mechanical and thermal properties. There has been a growing need and rapid development in large-area deposition of graphene film and its applications. Chemical vapour deposition on copper has emerged as one of the most promising methods in obtaining large-scale graphene films with quality comparable to exfoliated graphene. In this chapter, we review the synthesis and characterizations of graphene grown on copper foil substrates by atmospheric pressure chemical vapour deposition. We also discuss potential applications of such large scale synthetic graphene.
31 citations
TL;DR: In this article, the synthesis and characterizations of synthetic graphene grown on copper foil substrates by atmospheric pressure chemical vapor deposition are reviewed. And potential applications of such large-scale synthetic graphene are discussed.
Abstract: The discovery of graphene, a single layer of covalently bonded carbon atoms, has attracted intense interest. Initial studies using mechanically exfoliated graphene unveiled its remarkable electronic, mechanical and thermal properties. There has been a growing need and rapid development in large-area deposition of graphene film and its applications. Chemical vapor deposition on copper has emerged as one of the most promising methods in obtaining large-scale graphene films with quality comparable to exfoliated graphene. In this paper, we review the synthesis and characterizations of graphene grown on copper foil substrates by atmospheric pressure chemical vapor deposition. We also discuss potential applications of such large-scale synthetic graphene.
29 citations
TL;DR: In this paper, the authors observed that the Hall resistance of a homogeneous electron system is well known to be antisymmetric with respect to the magnetic field and the sign of charge carriers.
Abstract: The Hall resistance of a homogeneous electron system is well known to be antisymmetric with respect to the magnetic field and the sign of charge carriers. We have observed that such symmetries no longer hold in planar hybrid structures consisting of partly single layer graphene (SLG) and partly bilayer graphene (BLG) in the quantum Hall (QH) regime. In particular, the Hall resistance across the SLG and BLG interface is observed to exhibit quantized plateaus that switch between those characteristic of SLG QH states and BLG QH states when either the sign of the charge carriers (controlled by a back gate) or the direction of the magnetic field is reversed. Simultaneously reversing both the carrier type and the magnetic field gives rise to the same quantized Hall resistances. The observed SLG-BLG interface QH states, with characteristic asymmetries with respect to the signs of carriers and magnetic field, are determined only by the chirality of the QH edge states and can be explained by a Landauer-B\"uttiker analysis applied to such graphene hybrid structures involving two regions of different Landau level structures.
28 citations
01 Jan 2013
TL;DR: In this article, the growth mechanism and structural properties of pseudohexagonal Bi2Te3, Bi2Se3 and their alloys were successfully grown by molecular beam epitaxy (MBE) on GaAs (001) substrates.
Abstract: Films of pseudo-hexagonal Bi2Te3, Bi2Se3, and their alloys were successfully grown by molecular beam epitaxy (MBE) on GaAs (001) substrates. The growth mechanism and structural properties of these films were investigated by reflection high-energy electron diffraction (RHEED), atomic force microscopy (AFM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy and mapping. The results indicate that the epitaxial films are highly uniform and of high crystalline quality. The electronic band structure of these films was studied by angle-resolved photoemission spectroscopy (ARPES). The results confirm that these films are topological insulators, with a single Dirac cone for the topological surface states. Electric transport measurements were performed on the films, and weak anti-localization (WAL) was observed in the magnetoresistance. Tuning of conductance by gating was demonstrated in top-gated field effect transistor (FET) devices fabricated from these films.
4 citations
TL;DR: In this article, the transport properties of BTS221 from the thermoelectrics perspective were studied. But the authors focused on the surface dominant transports in their sample at low T. They also reported Seebeck measurement between 50K to room T.
Abstract: Bi2Te2Se (BTS221) bulk crystals were recently discovered as an intrinsic 3D topological insulator. We have synthesized this material, and studied the transport properties of BTS221 from the thermoelectrics perspective. Temperature (T) dependent resistivity measurement indicates surface dominant transports in our sample at low T. We also report Seebeck measurement between 50K to room T.