Research output: Contribution to journal › Article › peer-review
Effect of electron injection in copper-contacted graphene nanoribbons. / Simonov, Konstantin A.; Vinogradov, Nikolay A.; Vinogradov, Alexander S.; Generalov, Alexander V.; Svirskiy, Gleb I.; Cafolla, Attilio A.; Mårtensson, Nils; Preobrajenski, Alexei B.
In: Nano Research, Vol. 9, No. 9, 01.09.2016, p. 2735-2746.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Effect of electron injection in copper-contacted graphene nanoribbons
AU - Simonov, Konstantin A.
AU - Vinogradov, Nikolay A.
AU - Vinogradov, Alexander S.
AU - Generalov, Alexander V.
AU - Svirskiy, Gleb I.
AU - Cafolla, Attilio A.
AU - Mårtensson, Nils
AU - Preobrajenski, Alexei B.
N1 - Publisher Copyright: © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - For practical electronic device applications of graphene nanoribbons (GNRs), it is essential to have abrupt and well-defined contacts between the ribbon and the adjacent metal lead. By analogy with graphene, these contacts can induce electron or hole doping, which may significantly affect the I/V characteristics of the device. Cu is among the most popular metals of choice for contact materials. In this study, we investigate the effect of in situ intercalation of Cu on the electronic structure of atomically precise, spatially aligned armchair GNRs of width N = 7 (7-AGNRs) fabricated via a bottom-up method on the Au(788) surface. Scanning tunneling microscopy data reveal that the complete intercalation of about one monolayer of Cu under 7-AGNRs can be facilitated by gentle annealing of the sample at 80 °C. Angle-resolved photoemission spectroscopy (ARPES) data clearly reflect the one-dimensional character of the 7-AGNR band dispersion before and after intercalation. Moreover, ARPES and core-level photoemission results show that intercalation of Cu leads to significant electron injection into the nanoribbons, which causes a pronounced downshift of the valence and conduction bands of the GNR with respect to the Fermi energy (ΔE ~ 0.5 eV). As demonstrated by ARPES and X-ray absorption spectroscopy measurements, the effect of Cu intercalation is restricted to n-doping only, without considerable modification of the band structure of the GNRs. Post-annealing of the 7-AGNRs/Cu/Au(788) system at 200 °C activates the diffusion of Cu into Au and the formation of a Cu-rich surface Au layer. Alloying of intercalated Cu leads to the recovery of the initial position of GNR-related bands with respect to the Fermi energy (EF), thus, proving the tunability of the induced n-doping. [Figure not available: see fulltext.]
AB - For practical electronic device applications of graphene nanoribbons (GNRs), it is essential to have abrupt and well-defined contacts between the ribbon and the adjacent metal lead. By analogy with graphene, these contacts can induce electron or hole doping, which may significantly affect the I/V characteristics of the device. Cu is among the most popular metals of choice for contact materials. In this study, we investigate the effect of in situ intercalation of Cu on the electronic structure of atomically precise, spatially aligned armchair GNRs of width N = 7 (7-AGNRs) fabricated via a bottom-up method on the Au(788) surface. Scanning tunneling microscopy data reveal that the complete intercalation of about one monolayer of Cu under 7-AGNRs can be facilitated by gentle annealing of the sample at 80 °C. Angle-resolved photoemission spectroscopy (ARPES) data clearly reflect the one-dimensional character of the 7-AGNR band dispersion before and after intercalation. Moreover, ARPES and core-level photoemission results show that intercalation of Cu leads to significant electron injection into the nanoribbons, which causes a pronounced downshift of the valence and conduction bands of the GNR with respect to the Fermi energy (ΔE ~ 0.5 eV). As demonstrated by ARPES and X-ray absorption spectroscopy measurements, the effect of Cu intercalation is restricted to n-doping only, without considerable modification of the band structure of the GNRs. Post-annealing of the 7-AGNRs/Cu/Au(788) system at 200 °C activates the diffusion of Cu into Au and the formation of a Cu-rich surface Au layer. Alloying of intercalated Cu leads to the recovery of the initial position of GNR-related bands with respect to the Fermi energy (EF), thus, proving the tunability of the induced n-doping. [Figure not available: see fulltext.]
KW - angle-resolved photoemission spectroscopy (ARPES)
KW - bottom-up method
KW - charge injection
KW - copper intercalation
KW - graphene nanoribbons
KW - scanning tunneling microscopy
UR - http://www.scopus.com/inward/record.url?scp=84978733976&partnerID=8YFLogxK
U2 - 10.1007/s12274-016-1162-2
DO - 10.1007/s12274-016-1162-2
M3 - Article
VL - 9
SP - 2735
EP - 2746
JO - Nano Research
JF - Nano Research
SN - 1998-0124
IS - 9
ER -
ID: 7586626