Yesilpinar Damla, Schulze Lammers Bertram, Timmer Alexander, Amirjalayer Saeed, Fuchs Harald, Mönig Harry
Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany.
Nanoscale. 2020 Feb 7;12(5):2961-2965. doi: 10.1039/c9nr10450j. Epub 2020 Jan 23.
Functionalizing atomic force microscopy (AFM) tips by picking up single inert probe particles like CO or Xe from the surface drastically increase the resolution. In particular, this approach allows imaging organic molecules with submolecular resolution revealing their internal bonding structure. However, due to the weak coupling of these probe particles to both, the surface they are picked up from and the tip apex, these experiments require liquid helium temperatures (i.e.≈5 K). In the present study we demonstrate that functionalizing an AFM tip with an atomically defined O-terminated copper tip (CuOx tip) allows performing such experiments at liquid nitrogen temperatures (i.e.≈78 K) with outstanding quality. We show that it is possible to utilize CuOx tips for chemically selective imaging of a copper oxide nanodomain on a partially oxidized Cu(110) surface in the repulsive force regime at elevated temperatures. Moreover, the high structural and chemical stability of CuOx tips allow even ex situ investigations where these tips are used to perform experiments on other, non-Cu, non-oxidized, substrates. In particular, we present results obtained from a dicoronylene (DCLN) molecule with submolecular resolution. An analysis of inner and peripheral bond lengths of the DCLN molecule shows excellent agreement with theoretical gas phase simulations emphasizing the exceptional imaging properties of CuOx tips also at elevated temperatures.
通过从表面拾取单个惰性探针粒子（如一氧化碳或氙）来对原子力显微镜（AFM）探针进行功能化处理，可大幅提高分辨率。特别地，这种方法能够以亚分子分辨率对有机分子进行成像，揭示其内部键合结构。然而，由于这些探针粒子与它们所拾取的表面以及探针尖端的耦合较弱，这些实验需要液氦温度（即约5 K）。在本研究中，我们证明用原子级定义的O端铜探针（CuOx探针）对AFM探针进行功能化处理，能够在液氮温度（即约78 K）下以优异的质量进行此类实验。我们表明，在高温下的排斥力模式下，利用CuOx探针可以对部分氧化的Cu(110)表面上的氧化铜纳米域进行化学选择性成像。此外，CuOx探针的高结构和化学稳定性甚至允许进行异位研究，即在这些探针用于对其他非铜、未氧化的衬底进行实验的情况下。特别地，我们展示了从具有亚分子分辨率的二冠烯（DCLN）分子获得的结果。对DCLN分子内部和外围键长的分析表明，与理论气相模拟结果高度吻合，这突出了CuOx探针即使在高温下也具有出色的成像特性。
