发表机构
University of California, Berkeley; Lawrence Berkeley National Laboratory; Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory; Department of Chemistry, Columbia University; Department of Physics, University of Illinois Urbana-Champaign; Department of Physics, Cornell University; Department of Materials Science and Nanoengineering, Rice University（加州大学伯克利分校; 劳伦斯伯克利国家实验室; 加州大学伯克利分校与劳伦斯伯克利国家实验室卡弗里能源纳米科学研究所; 哥伦比亚大学化学系; 伊利诺伊大学厄巴纳-香槟分校物理系; 康奈尔大学物理系; 莱斯大学材料科学与纳米工程系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过顺序表面合成与STM诱导脱氢，在半导体石墨烯纳米带中直接写入金属片段，形成原子级精确的金属-半导体异质结，为低势垒p型接触提供新途径。
AI 中文摘要
石墨烯纳米带（GNRs）是一类高度可调的一维（1D）量子材料，可通过自下而上的合成方法制备。对GNR带隙和带边对齐的精确控制使其成为有前景的纳米电子学平台，但形成高质量电子界面仍然具有挑战性。在此，我们结合顺序表面合成和扫描隧道显微镜（STM）诱导的脱氢反应，直接将金属性7-iGNR片段写入原本为半导体性的H$_2$-7-iGNR中，且不改变GNR宽度或碳骨架连接性。所得金属片段在费米能级（$E_\mathrm{F}$）处具有非零谱权重，并表现出空间扩展的电子态，与两条色散带穿越$E_\mathrm{F}$一致。新的金属态可由扩展的Su-Schrieffer-Heeger锯齿形梯子哈密顿量很好地描述。扫描隧道谱（STS）和第一性原理计算表明，相邻连接半导体GNR片段的价带边在金属片段处靠近$E_\mathrm{F}$。STS谱在金属-半导体GNR界面两侧约1 nm范围内恢复体相GNR性质，且无明显耗尽区。观察到的GNR带边对齐与空穴注入的小能垒一致，从而为未来基于GNR的电子器件实现原子级精确、低势垒p型接触提供了可能途径。
英文摘要
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 ($E_\mathrm{F}$) and spatially extended electronic states, consistent with two dispersive bands crossing $E_\mathrm{F}$. 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 $E_\mathrm{F}$ for the metallic segments. STS spectra recover bulk GNR properties within $\sim$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.
Comments22 pages, 7 figures
