TY - JOUR
T1 - Alignment of semiconducting graphene nanoribbons on vicinal Ge(001)
AU - Jacobberger, Robert M.
AU - Murray, Ellen A.
AU - Fortin-Deschênes, Matthieu
AU - Göltl, Florian
AU - Behn, Wyatt A.
AU - Krebs, Zachary J.
AU - Levesque, Pierre L.
AU - Savage, Donald E.
AU - Smoot, Charles
AU - Lagally, Max G.
AU - Desjardins, Patrick
AU - Martel, Richard
AU - Brar, Victor
AU - Moutanabbir, Oussama
AU - Mavrikakis, Manos
AU - Arnold, Michael S.
N1 - Publisher Copyright:
© 2019 The Royal Society of Chemistry.
PY - 2019/3/21
Y1 - 2019/3/21
N2 - Chemical vapor deposition of CH4 on Ge(001) can enable anisotropic growth of narrow, semiconducting graphene nanoribbons with predominately smooth armchair edges and high-performance charge transport properties. However, such nanoribbons are not aligned in one direction but instead grow perpendicularly, which is not optimal for integration into high-performance electronics. Here, it is demonstrated that vicinal Ge(001) substrates can be used to synthesize armchair nanoribbons, of which ∼90% are aligned within ±1.5° perpendicular to the miscut. When the growth rate is slow, graphene crystals evolve as nanoribbons. However, as the growth rate increases, the uphill and downhill crystal edges evolve asymmetrically. This asymmetry is consistent with stronger binding between the downhill edge and the Ge surface, for example due to different edge termination as shown by density functional theory calculations. By tailoring growth rate and time, nanoribbons with sub-10 nm widths that exhibit excellent charge transport characteristics, including simultaneous high on-state conductance of 8.0 μS and a high on/off conductance ratio of 570 in field-effect transistors, are achieved. Large-area alignment of semiconducting ribbons with promising charge transport properties is an important step towards understanding the anisotropic nanoribbon growth and integrating these materials into scalable, future semiconductor technologies.
AB - Chemical vapor deposition of CH4 on Ge(001) can enable anisotropic growth of narrow, semiconducting graphene nanoribbons with predominately smooth armchair edges and high-performance charge transport properties. However, such nanoribbons are not aligned in one direction but instead grow perpendicularly, which is not optimal for integration into high-performance electronics. Here, it is demonstrated that vicinal Ge(001) substrates can be used to synthesize armchair nanoribbons, of which ∼90% are aligned within ±1.5° perpendicular to the miscut. When the growth rate is slow, graphene crystals evolve as nanoribbons. However, as the growth rate increases, the uphill and downhill crystal edges evolve asymmetrically. This asymmetry is consistent with stronger binding between the downhill edge and the Ge surface, for example due to different edge termination as shown by density functional theory calculations. By tailoring growth rate and time, nanoribbons with sub-10 nm widths that exhibit excellent charge transport characteristics, including simultaneous high on-state conductance of 8.0 μS and a high on/off conductance ratio of 570 in field-effect transistors, are achieved. Large-area alignment of semiconducting ribbons with promising charge transport properties is an important step towards understanding the anisotropic nanoribbon growth and integrating these materials into scalable, future semiconductor technologies.
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U2 - 10.1039/c9nr00713j
DO - 10.1039/c9nr00713j
M3 - Article
C2 - 30821309
AN - SCOPUS:85062854619
SN - 2040-3364
VL - 11
SP - 4864
EP - 4875
JO - Nanoscale
JF - Nanoscale
IS - 11
ER -