Berdonces-Layunta Alejandro, Lawrence James, Edalatmanesh Shayan, Castro-Esteban Jesús, Wang Tao, Mohammed Mohammed S G, Colazzo Luciano, Peña Diego, Jelínek Pavel, de Oteyza Dimas G
Donostia International Physics Center, 20018 San Sebastián, Spain.
Centro de Física de Materiales, 20018 San Sebastián, Spain.
ACS Nano. 2021 Mar 23;15(3):5610-5617. doi: 10.1021/acsnano.1c00695. Epub 2021 Mar 3.
Nanostructured graphene has been widely studied in recent years due to the tunability of its electronic properties and its associated interest for a variety of fields, such as nanoelectronics and spintronics. However, many of the graphene nanostructures of technological interest are synthesized under ultrahigh vacuum, and their limited stability as they are brought out of such an inert environment may compromise their applicability. In this study, a combination of bond-resolving scanning probe microscopy (BR-SPM), along with theoretical calculations, has been employed to study (3,1)-chiral graphene nanoribbons [(3,1)-chGNRs] that were synthesized on a Au(111) surface and then exposed to oxidizing environments. Exposure to the ambient atmosphere, along with the required annealing treatment to desorb a sufficiently large fraction of contaminants to allow for its postexposure analysis by BR-SPM, revealed a significant oxidation of the ribbons, with a dramatically disruptive effect on their electronic properties. More controlled experiments avoiding high temperatures and exposing the ribbons only to low pressures of pure oxygen show that also under these more gentle conditions the ribbons are oxidized. From these results, we obtain additional insights into the preferential reaction sites and the nature of the main defects that are caused by oxygen. We conclude that graphene nanoribbons with zigzag edge segments require forms of protection before they can be used in or transferred through ambient conditions.
近年来，由于纳米结构石墨烯的电子特性具有可调节性，且在纳米电子学和自旋电子学等多个领域具有潜在应用价值，因此受到了广泛研究。然而，许多具有技术应用前景的石墨烯纳米结构是在超高真空条件下合成的，当它们从这种惰性环境中取出时，其稳定性有限，这可能会影响它们的实际应用。在本研究中，结合键分辨扫描探针显微镜（BR-SPM）和理论计算，对在Au(111)表面合成并暴露于氧化环境中的(3,1)-手性石墨烯纳米带[(3,1)-chGNRs]进行了研究。将纳米带暴露于大气环境中，并进行所需的退火处理以解吸足够多的污染物，以便通过BR-SPM进行暴露后分析，结果显示纳米带发生了显著氧化，对其电子特性产生了极大的破坏作用。通过避免高温且仅将纳米带暴露于低气压纯氧环境的更可控实验表明，在这些更温和的条件下，纳米带也会被氧化。从这些结果中，我们对优先反应位点以及由氧引起的主要缺陷的性质有了进一步的认识。我们得出结论，具有锯齿形边缘段的石墨烯纳米带在能够在环境条件下使用或转移之前，需要采取某种形式的保护措施。
