Observations of Individual Cu-Phthalocyanine Molecules Deposited on Nano-Tips in the Field Emission Microscope

Rezeq, Moh’d; Joachim, Christian; Lwin, Ma Han Thu; Navarro, Francisco Ample

doi:10.1007/978-3-642-38809-5_1

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…Around the protrusion, electric elds are further enhanced, and an electron emission is driven from the molecules at the top of the protrusions. However, it was not clear whether the molecules at the top are single or clustered [7][8][9][10][11][12][13], unless one could undertake an exceptional study with an ultra-sharp tip [14] or a single molecule emitter [15]. For instance, the authors in reference [10] consider the protrusions to consist of a cluster of oxygen atoms, and each spot in the emission patterns representing a single atom.…”

Section: Introductionmentioning

confidence: 99%

Field emission microscope for a single fullerene molecule

Yanagisawa

Bohn

Goschin

et al. 2022

Preprint

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Applying strong direct current (DC) electric fields on the apex of a sharp metallic tip, electrons can be radially emitted from the apex to vacuum. Subsequently, they magnify the nanoscopic information on the apex, which serves as a field emission microscope (FEM). When depositing molecules on such a tip, peculiar electron emission patterns such as clover leaves appear. These phenomena were first observed seventy years ago. However, the source of these emission patterns has not yet been identified owing to the limited experimental information about molecular configurations on a tip. Here, we used fullerene molecules and characterized the molecule-covered tip by an FEM. In addition to the experiments, simulations were performed to obtain optimized molecular configurations on a tip. Both results indicate that the molecules, the source of the peculiar emission patterns, appear on a molecule layer formed on the tip under strong DC electric fields. Furthermore, the simulations revealed that these molecules are mostly isolated single molecules forming single-molecule-terminated protrusions. Upon the excellent agreements in both results, we concluded that each emission pattern originates from a single molecule. Our work should pave the way to revive old-fashioned electron microscopy as a powerful tool for investigating a single molecule.

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