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Small gap semiconducting organic charge-transfer interfaces

Nakano, M. (author), Alves, H. (author), Molinari, A.S. (author), Ono, S. (author), Minder, N. (author), Morpurgo, A.F. (author)

We investigated transport properties of organic heterointerfaces formed by single-crystals of two organic donor-acceptor molecules, tetramethyltetraselenafulvalene and 7,7,8,8-tetracyanoquinodimethane (TCNQ). Whereas the individual crystals have unmeasurably high resistance, the interface exhibits a resistivity of few tens of megohm with a...

journal article 2010

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Magnetotransport through graphene nanoribbons

Oostinga, J.B. (author), Sacépé, B. (author), Craciun, M.F. (author), Morpurgo, A.F. (author)

We investigate magnetotransport through graphene nanoribbons as a function of gate and bias voltage, and temperature. We find that a magnetic field systematically leads to an increase in the conductance on a scale of a few tesla. This phenomenon is accompanied by a decrease in the energy scales associated to charging effects, and to hopping...

journal article 2010

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Quantitative analysis of density-dependent transport in tetramethyltetraselenafulvalene single-crystal transistors: Intrinsic properties and trapping

Xie, H. (author), Alves, H. (author), Morpurgo, A.F. (author)

We perform a combined experimental and theoretical study of tetramethyltetraselenafulvalene (TMTSF) single-crystal field-effect transistors, whose electrical characteristics exhibit clear signatures of the intrinsic transport properties of the material. We present a simple, well-defined model based on physical parameters and we successfully...

journal article 2009

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Electrostatic confinement of electrons in graphene nanoribbons

Liu, X. (author), Oostinga, J.B. (author), Morpurgo, A.F. (author), Vandersypen, L.M.K. (author)

Coulomb blockade is observed in a graphene nanoribbon device with a top gate. When two pn junctions are formed via the back gate and the local top gate, electrons are confined between the pn junctions which act as the barriers. When no pn junctions are induced by the gate voltages, electrons are still confined, as a result of strong disorder,...

journal article 2009

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Evidence for the formation of a Mott state in potassium-intercalated pentacene

Craciun, M.F. (author), Giovannetti, G. (author), Rogge, S. (author), Brocks, G. (author), Morpurgo, A.F. (author), Van den Brink, J. (author)

We investigate electronic transport through pentacene thin films intercalated with potassium. From temperature-dependent conductivity measurements we find that potassium-intercalated pentacene shows metallic behavior in a broad range of potassium concentrations. Surprisingly, the conductivity exhibits a re-entrance into an insulating state when...

journal article 2009

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Shot Noise in Ballistic Graphene

Danneau, R. (author), Wu, F. (author), Craciun, M.F. (author), Russo, S. (author), Tomi, M.Y. (author), Salmilehto, J. (author), Morpurgo, A.F. (author), Hakonen, P.J. (author)

journal article 2008

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Quantitative analysis of electronic transport through weakly coupled metal/organic interfaces

Molinari, A.S. (author), Gutiérrez Lezama, I. (author), Parisse, P. (author), Takenobu, T. (author), Iwasa, Y. (author), Morpurgo, A.F. (author)

Using single-crystal transistors, we have performed a systematic experimental study of electronic transport through oxidized copper/rubrene interfaces as a function of temperature and bias. We find that the measurements can be quantitatively reproduced in terms of the thermionic emission theory for Schottky diodes, if the effect of the bias...

journal article 2008

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Topological Confinement in Bilayer Graphene

Martin, I. (author), Blanter, Y.M. (author), Morpurgo, A.F. (author)

We study a new type of one-dimensional chiral states that can be created in bilayer graphene (BLG) by electrostatic lateral confinement. These states appear on the domain walls separating insulating regions experiencing the opposite gating polarity. While the states are similar to conventional solitonic zero modes, their properties are defined...

journal article 2008

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Current saturation and Coulomb interactions in organic single-crystal transistors

Fratini, S. (author), Xie, H. (author), Hulea, I.N. (author), Ciuchi, S. (author), Morpurgo, A.F. (author)

journal article 2008

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Bias-dependent contact resistance in rubrene single-crystal field-effect transistors

Molinari, A. (author), Gutiérrez, I. (author), Hulea, I.N. (author), Russo, S. (author), Morpurgo, A.F. (author)

The authors report a systematic study of the bias-dependent contact resistance in rubrene single-crystal field-effect transistors with Ni, Co, Cu, Au, and Pt electrodes. They show that the reproducibility in the values of contact resistance strongly depends on the metal, ranging from a factor of 2 for Ni to more than three orders of magnitude...

journal article 2007

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Adiabatic Quantum Pumping at the Josephson Frequency

Russo, S. (author), Tobiska, J. (author), Klapwijk, T.M. (author), Morpurgo, A.F. (author)

journal article 2007

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Aharonov-Bohm effect and broken valley degeneracy in graphene rings

Recher, P. (author), Trauzettel, B. (author), Rycerz, A. (author), Blanter, Ya.M. (author), Beenakker, C.W.J. (author), Morpurgo, A.F. (author)

journal article 2007

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Photon-assisted electron transport in graphene: Scattering theory analysis

Trauzettel, B. (author), Blanter, Y.M. (author), Morpurgo, A.F. (author)

journal article 2007

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Intervalley Scattering, Long-Range Disorder, and Effective Time-Reversal Symmetry Breaking in Graphene

Morpurgo, A.F. (author), Guinea, F. (author)

We discuss the effect of certain types of static disorder, like that induced by curvature or topological defects, on the quantum correction to the conductivity in graphene. We find that when the intervalley scattering time is long or comparable to ?ø these defects can induce an effective time-reversal symmetry breaking of the Hamiltonian...

journal article 2006

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Electrostatic modification of novel materials

Ahn, C.H. (author), Bhattacharya, A. (author), Di Ventra, M. (author), Eckstein, J.N. (author), Frisbie, C.D. (author), Gershenson, M.E. (author), Goldman, A.M. (author), Inoue, I.H. (author), Mannhart, J. (author), Millis, A.J. (author), Morpurgo, A.F. (author), Natelson, D. (author), Triscone, J.M. (author)

Application of the field-effect transistor principle to novel materials to achieve electrostatic doping is a relatively new research area. It may provide the opportunity to bring about modifications of the electronic and magnetic properties of materials through controlled and reversible changes of the carrier concentration without modifying the...

journal article 2006

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Colloquium: Electronic transport in single-crystal organic transistors

Gershenson, M.E. (author), Podzorov, V. (author), Morpurgo, A.F. (author)

Small-molecule organic semiconductors, together with polymers, form the basis for the emerging field of organic electronics. Despite the rapid technological progress in this area, our understanding of fundamental electronic properties of these materials remains limited. Recently developed organic field-effect transistors (OFETs) based on single...

journal article 2006

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Reproducible low contact resistance in rubrene single-crystal field-effect transistors with nickel electrodes

Hulea, I.N. (author), Russo, S. (author), Molinari, A. (author), Morpurgo, A.F. (author)

We have investigated the contact resistance of rubrene single-crystal field-effect transistors (FETs) with nickel electrodes by performing scaling experiments on devices with channel length ranging from 200 nm up to 300??m. We find that the contact resistance can be as low as 100???cm with narrowly spread fluctuations. For comparison, we have...

journal article 2006

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Spin-dependent quantum interference in single-wall carbon nanotubes with ferromagnetic contacts

Man, H.T. (author), Wever, I.J.W. (author), Morpurgo, A.F. (author)

journal article 2006

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Nanospintronics with carbon nanotubes

Cottet, A. (author), Kontos, T. (author), Sahoo, S. (author), Man, H.T. (author), Choi, M.S. (author), Belzig, W. (author), Bruder, C. (author), Morpurgo, A.F. (author), Schönenberger, C. (author)

journal article 2006

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Ambipolar Cu- and Fe-phthalocyanine single-crystal field-effect transistors

De Boer, R.W.I. (author), Stassen, A.F. (author), Craciun, M.F. (author), Mulder, C.L. (author), Molinari, A. (author), Rogge, S. (author), Morpurgo, A.F. (author)

We report the observation of ambipolar transport in field-effect transistors fabricated on single crystals of copper- and iron-phthalocyanine, using gold as a high work-function metal for the fabrication of source and drain electrodes. In these devices, the room-temperature mobility of holes reaches 0.3?cm2/V?s in both materials. The highest...

journal article 2005