With its ability to probe individual graphene flakes, providing nanoscale detail to the atomic level, atomic force microscopy has been part of graphene research since Geim and Novoselov’s Nobel prize winning discovery started the field. The early TappingMode images, acquired with aBruker MultiMode®AFM在通过光学调查点上的位置,明确识别了以前认为无法访问的单一石墨烯层。
这一发现之后的几年发生了石墨烯研究活动的爆炸,使用了100多个出版物Bruker AFMS。这些研究包括对石墨烯和氧化石墨烯的制造的研究,其中一致的产品纯度和已知的低缺陷密度是一个关键挑战,尤其是对于可扩展的石墨烯生产。他们还解决了对于石墨烯设想的广泛的应用程序,从柔性显示器和快速电子设备到执行器,生物传感器和复合材料。几乎每个领先的石墨烯研究中心的研究人员也在使用我们维度XR,Dimension FastScan®andDimension Icon®systems to drive their research in graphene and other 2D materials.
先进的物业测量在石墨烯研究中令人兴奋的AFM发现中起着关键作用。这项研究包括与布鲁克独家的定量机械属性映射PeakForce QNM®as utilized by Chu et al (J. Procedia Eng 36, 571 (2012) for unraveling graphene layering and by Lazar et al (J. ACS Nano ASAP 2013) for quantifying the graphene metal interactions controlling the electrode bonding in electrical device applications. Other examples are the nanoscale conductivity investigations on composites (Bhaskar et al., J. Power Sources 216, 169, 2012) and functionalized graphene (Felten et al., Small 9 (4), 631, 2013), as well as KPFM investigations clarifying the charge percolation pathway in optimized graphene oxide – organic hybrid FET devices (Liscio et al., J. Materials Chem 21, 2924, 2011).
The latest Bruker technology promises more exciting advances yet to come.Peakforce KPFM™may permit extending the hybrid device investigations to higher spatial resolution, more quantitative measurements, and correlation with local material variations that could be revealed in simultaneous mechanical property mapping. Future conductivity studies may benefit from the proven ability ofPeakForce TUNA™在最脆弱的样品上提供最高的空间分辨率。进一步的峰值QNM研究可能会富含对2D材料石墨烯缺陷的研究,因为已经在3D晶体上显示了这种模式,以打开具有原子缺陷分辨率的属性映射的大门。
Topographic map of graphene flake prepared on silicon dioxide, reveals expected 300pm graphene step between successive layers.
石墨烯薄片拉曼G波段。拉曼光谱允许通过G波段强度快速映射石墨烯层结构。
The intensity of the D-band around 1350cm-1indicates disorder of the graphene lattice. This D-band image suggests an area of increased defects along the edge of the single-layer portion of the sample.
The PeakForce KPFM image shows the single to bilayer graphene workfunction change to be 80mV, but then decreasing with each successive layer.
AFM topography image showing wrinkles in graphene layers at area of interest.
The detailed mechanical property measurements of the defect rich area reveal fine structures with greater compliance and reduced adhesion compared to the undisturbed portion of the layer, suggesting the graphene layer is wrinkled in this area.
The deformation channel shows a larger deformation on the graphene flake than on the substrate, and allows us to deduce that the graphene flake is softer than the silicon during loading, but does not mechanically relax during the sub-millisecond unloading.
This modulus image shows fine structures with greater compliance seen as darker areas on the modulus map image.