We present a method to establish inner point contacts with dimensions as small as 100 nm on hexagonal boron nitride (hBN) encapsulated graphene heterostructures by pre-patterning the top-hBN in a separate step prior to dry-stacking. 2- and 4-terminal field effect measurements between different lead combinations are in qualitative agreement with an electrostatic model assuming point-like contacts. The measured contact resistances are 0.5–1.5 kΩ per contact, which is quite low for such small contacts. By applying a perpendicular magnetic field, an insulating behaviour in the quantum Hall regime was observed, as expected for inner contacts. The fabricated contacts are compatible with high mobility graphene structures and open up the field for the realization of several electron optical proposals.
References
1.
P.
Rickhaus
, R.
Maurand
, M.-H.
Liu
, M.
Weiss
, K.
Richter
, and C.
Schnenberger
, “Ballistic interferences in suspended graphene
,” Nat. Commun.
4
, 2342
(2013
).2.
A. L.
Grushina
, D.-K.
Ki
, and A. F.
Morpurgo
, “A ballistic pn junction in suspended graphene with split bottom gates
,” Appl. Phys. Lett.
102
(22
), 223102
(2013
).3.
L. C.
Campos
, A. F.
Young
, K.
Surakitbovorn
, K.
Watanabe
, T.
Taniguchi
, and P.
Jarillo-Herrero
, “Quantum and classical confinement of resonant states in a trilayer graphene fabry-perot interferometer
,” Nat. Commun.
3
, 1239
(2012
).4.
P.
Rickhaus
, P.
Makk
, M.-H.
Liu
, E.
Tóvári
, M.
Weiss
, R.
Maurand
, K.
Richter
, and C.
Schönenberger
, “Snake trajectories in ultraclean graphene p-n junctions
,” Nat. Commun.
6
, 6470
(2015
).5.
T.
Taychatanapat
, J. Y.
Tan
, Y.
Yeo
, K.
Watanabe
, T.
Taniguchi
, and B.
Özyilmaz
, “Conductance oscillations induced by ballistic snake states in a graphene heterojunction
,” Nat. Commun.
6
, 6093
(2015
).6.
P.
Rickhaus
, M.-H.
Liu
, P.
Makk
, R.
Maurand
, S.
Hess
, S.
Zihlmann
, M.
Weiss
, K.
Richter
, and K.
Schönenberger
, “Guiding of electrons in a few-mode ballistic graphene channel
,” Nano Lett.
15
, 5819
(2015
).7.
T.
Taychatanapat
, K.
Watanabe
, T.
Taniguchi
, and P.
Jarillo-Herrero
, “Electrically tunable transverse magnetic focusing in grapheme
,” Nat. Phys.
9
(4
), 225
–229
(2013
).8.
V. E.
Calado
, S.-E.
Zhu
, S.
Goswami
, Q.
Xu
, K.
Watanabe
, T.
Taniguchi
, G. C. A. M.
Janssen
, and L. M. K.
Vandersypen
, “Ballistic transport in graphene grown by chemical vapor deposition
,” Appl. Phys. Lett.
104
(2
), 023103
(2014
).9.
N.
Mizuno
, B.
Nielsen
, and X.
Du
, “Ballistic-like supercurrent in suspended graphene Josephson weak links
,” Nat. Commun.
4
, 2716
(2013
).10.
V. E.
Calado
, S.
Goswami
, G.
Nanda
, M.
Diez
, A. R.
Akhmerov
, K.
Watanabe
, T.
Taniguchi
, T. M.
Klapwijk
, and L. M. K.
Vandersypen
, “Ballistic Josephson junctions in edge-contacted grapheme
,” Nature Nanotechnology
10
, 761
–764
(2015
).11.
M.
Ben Shalom
, M. J.
Zhu
, V. I.
Falko
, A.
Mishchenko
, A. V.
Kretinin
, K. S.
Novoselov
, C. R.
Woods
, K.
Watanabe
, T.
Taniguchi
, A. K.
Geim
, and J. R.
Prance
, “Proximity superconductivity in ballistic graphene, from fabry-perot oscillations to random Andreev states in magnetic field
,” e-print arXiv:1504.03286.12.
M. T.
Allen
, O.
Shtanko
, I. C.
Fulga
, J. I.-J.
Wang
, D.
Nurgaliev
, K.
Watanabe
, T.
Taniguchi
, A. R.
Akhmerov
, P.
Jarillo-Herrero
, L. S.
Levitov
, and A.
Yacoby
, “Visualization of phase-coherent electron interference in a ballistic graphene Josephson junction
,” e-print arXiv:1506.06734.13.
A. V.
Kretinin
, Y.
Cao
, J. S.
Tu
, G. L.
Yu
, R.
Jalil
, K. S.
Novoselov
, S. J.
Haigh
, A.
Gholinia
, A.
Mishchenko
, M.
Lozada
, T.
Georgiou
, C. R.
Woods
, F.
Withers
, P.
Blake
, G.
Eda
, A.
Wirsig
, C.
Hucho
, K.
Watanabe
, T.
Taniguchi
, A. K.
Geim
, and R. V.
Gorbachev
, “Electronic properties of graphene encapsulated with different two-dimensional atomic crystals
,” Nano Lett.
14
(6
), 3270
(2014
).14.
L.
Wang
, I.
Meric
, P. Y.
Huang
, Q.
Gao
, Y.
Gao
, H.
Tran
, T.
Taniguchi
, K.
Watanabe
, L. M.
Campos
, D. A.
Muller
, J.
Guo
, P.
Kim
, J.
Hone
, K. L.
Shepard
, and C. R.
Dean
, “One-dimensional electrical contact to a two-dimensional material
,” Science
342
(6158
), 614
(2013
).15.
V. G.
Veselago
, “The electrodynamics of substances with simultaneously negatives of ϵ and μ
,” Sov. Phys. Usp.
10
, 509
(1968
).16.
V. V.
Cheianov
, V.
Fal'ko
, and B. L.
Altshuler
, “The focusing of electron flow and a veselago lens in graphene p-n junctions
,” Science
315
(5816
), 1252
(2007
).17.
S.
Gómez
, P.
Burset
, W. J.
Herrera
, and A.
Levy Yeyati
, “Selective focusing of electrons and holes in a graphene-based superconducting lens
,” Phys. Rev. B
85
, 115411
(2012
).18.
G.-H.
Lee
, G.-H.
Park
, and H.-J.
Lee
, “Observation of negative refraction of dirac fermions in grapheme
,” Nature Physics
(2015
).19.
J. L.
Garcia-Pomar
, A.
Cortijo
, and M.
Nieto-Vesperinas
, “Fully valley-polarized electron beams in grapheme
,” Phys. Rev. Lett.
100
, 236801
(2008
).20.
C. G.
Péterfalvi
, L.
Oroszlány
, C. J.
Lambert
, and J.
Cserti
, “Intraband electron focusing in bilayer graphene
,” New J. Phys.
14
, 063028
(2012
).21.
A. G.
Moghaddam
and M.
Zareyan
, “Graphene-based electronic spin lenses
,” Phys. Rev. Lett.
105
, 146803
(2010
).22.
A. A.
Patel
, N.
Davies
, V.
Cheianov
, and V. I.
Fal'ko
, “Classical and quantum magneto-oscillations of current flow near a p-n junction in graphene
,” Phys. Rev. B
86
, 081413
(2012
).23.
N.
Davies
, A. A.
Patel
, A.
Cortijo
, V.
Cheianov
, F.
Guinea
, and V. I.
Fal'ko
, “Skipping and snake orbits of electrons: Singularities and catastrophes
,” Phys. Rev. B
85
, 155433
(2012
).24.
Y.
Zhao
, P.
Cadden-Zimansky
, F.
Ghahari
, and P.
Kim
, “Magnetoresistance measurements of graphene at the charge neutrality point
,” Phys. Rev. Lett.
108
, 106804
(2012
).25.
C. R.
Dean
, A. F.
Young
, I.
Meric
, C.
Lee
, L.
Wang
, S.
Sorgenfrei
, K.
Watanabe
, T.
Taniguchi
, P.
Kim
, K. L.
Shepard
, and J.
Hone
, “Boron nitride substrates for high-quality graphene electronics
,” Nat. Nanotechnol.
5
, 722
(2010
).26.
P. J.
Zomer
, M. H. D.
Guimarães
, J. C.
Brant
, N.
Tombros
, and B. J.
van Wees
, “Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride
,” Appl. Phys. Lett.
105
, 013101
(2014
).27.
A.
Castellanos-Gomez
, M.
Buscema
, R.
Molenaar
, V.
Singh
, L.
Janssen
, H. S. J.
van der Zant
, and G. A.
Steele
, “Deterministic transfer of two-dimensional materials by all-dry viscoelastic stamping
,” 2D Mater.
1
, 011002
(2014
).28.
L.
Banszerus
, M.
Schmitz
, S.
Engels
, J.
Dauber
, M.
Oellers
, F.
Haupt
, K.
Watanabe
, T.
Taniguchi
, B.
Beschoten
, and C.
Stampfer
, “Ultrahigh-mobility graphene devices from chemical vapor deposition on reusable copper
,” Sci. Adv.
1
(6
), e1500222
(2015
).29.
J. I-J.
Wang
, Y.
Yang
, Y.-A.
Chen
, K.
Watanabe
, T.
Taniguchi
, H. O. H.
Churchill
, and P.
Jarillo-Herrero
, “Electronic transport of encapsulated graphene and WSe2 devices fabricated by pick-up of prepatterned hBN
,” Nano Lett.
15
(3
), 1898
–1903
(2015
).30.
L.
Onsager
, “Reciprocal relations in irreversible processes. I
,” Phys. Rev.
37
, 405
(1931
).31.
See supplementary material at http://dx.doi.org/10.1063/1.4935032 for details of sample fabrication, for Raman and additional magnetic field measurements.
32.
P.
Zhang
, Y. Y.
Lau
, and R. S.
Timsit
, “On the spreading resistance of thin-film contacts
,” IEEE Trans. Electron Devices
59
(7
), 1936
(2012
).33.
J. C.
Maxwell
, A Treatise on Electricity and Magnetism
(Clarendon Press
, Oxford
, 1904
).© 2015 AIP Publishing LLC.
2015
AIP Publishing LLC
You do not currently have access to this content.
