Kinikar Amogh, Xiang Feifei, Palomino-Ruiz Lucia, Lu Li-Syuan, Dong Chengye, Gu Yanwei, Darawish Rimah, Ammerman Eve, Gröning Oliver, Müllen Klaus, Fasel Roman, Robinson Joshua A, Ruffieux Pascal, Schuler Bruno, Borin Barin Gabriela
nanotech@surfaces laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
Departamento de Química Orgánica, Facultad de Ciencias, Unidad de Excelencia de Química Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, 18071 Granada, Spain.
ACS Appl Nano Mater. 2025 Aug 12;8(33):16457-16464. doi: 10.1021/acsanm.5c02753. eCollection 2025 Aug 22.
On-surface synthesis enables the fabrication of atomically precise graphene nanoribbons (GNRs) with properties defined by their shape and edge topology. While this bottom-up approach provides unmatched control over electronic and structural characteristics, integrating GNRs into functional electronic devices requires their transfer from noble metal growth surfaces to technologically relevant substrates. However, such transfers often induce structural modifications, potentially degrading or eliminating GNRs' desired functionality - a process that remains poorly understood. In this study, we employ low-temperature scanning tunneling microscopy and spectroscopy (STM/STS) to characterize 9-atom-wide armchair GNRs (9-AGNRs) following polymer-free wet-transfer onto epitaxial graphene (EG) and quasi-freestanding epitaxial graphene (QFEG) substrates. Our results reveal that armchair GNRs maintain their structural integrity post-transfer, while GNRs with extended or modified edge topologies exhibit significant structural changes, including partial disintegration. Additionally, STS measurements reveal differences in the Fermi level alignment between GNRs and the graphene substrates, a key factor in optimizing carrier injection efficiency in electronic transport devices. This study establishes a framework for detecting postprocessing structural modifications in GNRs, which are often hidden in optical ensemble measurements. By addressing the challenges of substrate transfer and providing insights into GNR-substrate interactions, these findings pave the way for the reliable integration of atomically precise GNRs into next-generation nanoelectronic and optoelectronic devices.
表面合成能够制造出原子精确的石墨烯纳米带（GNR），其性质由形状和边缘拓扑结构决定。虽然这种自下而上的方法能对电子和结构特性进行无与伦比的控制，但将GNR集成到功能性电子器件中需要将其从贵金属生长表面转移到技术上相关的衬底上。然而，这种转移常常会引起结构改变，可能会降低或消除GNR所需的功能——这一过程仍知之甚少。在本研究中，我们采用低温扫描隧道显微镜和光谱（STM/STS）来表征在无聚合物湿法转移到外延石墨烯（EG）和准独立外延石墨烯（QFEG）衬底上后的9原子宽扶手椅型GNR（9-AGNR）。我们的结果表明，扶手椅型GNR在转移后保持其结构完整性，而具有扩展或修饰边缘拓扑结构的GNR则表现出显著的结构变化，包括部分解体。此外，STS测量揭示了GNR与石墨烯衬底之间费米能级对齐的差异，这是优化电子传输器件中载流子注入效率的关键因素。本研究建立了一个检测GNR后处理结构修饰的框架，这些修饰在光学整体测量中常常被隐藏。通过应对衬底转移的挑战并深入了解GNR与衬底的相互作用，这些发现为将原子精确的GNR可靠集成到下一代纳米电子和光电器件中铺平了道路。
