Synthesis of Metal-Semiconductor Heterojunctions in Single Graphene Nanoribbons
Abstract
Graphene nanoribbons (GNRs) are a highly tunable class of one-dimensional (1D) quantum materials that can be fabricated through bottom-up synthesis. Precise control over GNR band gaps and band-edge alignments has established them as a promising nanoelectronics platform, but forming high-quality electronic interfaces remains challenging. Here we combine sequential on-surface synthesis and scanning tunneling microscopy (STM)-induced dehydrogenation to directly write metallic 7-iGNR segments into otherwise semiconducting H2-7-iGNRs without changing the GNR width or carbon backbone connectivity. The resulting metallic segments exhibit nonzero spectral weight at the Fermi level (EF) and spatially extended electronic states, consistent with two dispersive bands crossing EF. The new metallic states are well described by an extended Su--Schrieffer--Heeger zigzag-ladder Hamiltonian. Scanning tunnelling spectroscopy (STS) and first-principles calculations show that the valence band edge of adjacent, connected semiconducting GNR segments lies close to EF for the metallic segments. STS spectra recover bulk GNR properties within ∼1 nm on either side of the metal-semiconductor GNR interface, with no discernible depletion region. The observed GNR band edge alignment is consistent with a small energy barrier for hole injection, thus suggesting a possible route towards atomically precise, low-barrier p-type contacts for future GNR-based electronic devices.
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BibTeX
@misc{wang2026synthesis,
title = {{Synthesis of Metal-Semiconductor Heterojunctions in Single Graphene Nanoribbons}},
author = {Ziyi Wang and Kaitlin Slicker and Weichen Tang and Boyu Qie and Rafal Zuzak and Haowen Pang and Yudi Huang and Xinheng Li and Peter H. Jacobse and Steven G. Louie and Felix R. Fischer and Michael F. Crommie},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.01194},
eprint = {2610.01194},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.01194},
}
RIS
TY - UNPB
TI - Synthesis of Metal-Semiconductor Heterojunctions in Single Graphene Nanoribbons
AU - Ziyi Wang
AU - Kaitlin Slicker
AU - Weichen Tang
AU - Boyu Qie
AU - Rafal Zuzak
AU - Haowen Pang
AU - Yudi Huang
AU - Xinheng Li
AU - Peter H. Jacobse
AU - Steven G. Louie
AU - Felix R. Fischer
AU - Michael F. Crommie
PY - 2026
DA - 2026/10/01
PB - arXiv
DO - 10.48550/arxiv.2610.01194
UR - https://arxiv.org/abs/2610.01194
AB - Graphene nanoribbons (GNRs) are a highly tunable class of one-dimensional (1D) quantum materials that can be fabricated through bottom-up synthesis. Precise control over GNR band gaps and band-edge alignments has established them as a promising nanoelectronics platform, but forming high-quality electronic interfaces remains challenging. Here we combine sequential on-surface synthesis and scanning tunneling microscopy (STM)-induced dehydrogenation to directly write metallic 7-iGNR segments into otherwise semiconducting H_2-7-iGNRs without changing the GNR width or carbon backbone connectivity. The resulting metallic segments exhibit nonzero spectral weight at the Fermi level (E_F) and spatially extended electronic states, consistent with two dispersive bands crossing E_F. The new metallic states are well described by an extended Su--Schrieffer--Heeger zigzag-ladder Hamiltonian. Scanning tunnelling spectroscopy (STS) and first-principles calculations show that the valence band edge of adjacent, connected semiconducting GNR segments lies close to E_F for the metallic segments. STS spectra recover bulk GNR properties within ∼1 nm on either side of the metal-semiconductor GNR interface, with no discernible depletion region. The observed GNR band edge alignment is consistent with a small energy barrier for hole injection, thus suggesting a possible route towards atomically precise, low-barrier p-type contacts for future GNR-based electronic devices.
ER -