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Posted: Jul 23, 2017
Functionalizing an AFM tip with a single hydrogen atom
(Nanowerk News) Researchers demonstrated the controlled vertical manipulation of a single hydrogen (H) atom using the tip of an atomic force microscope (AFM) sensor and its application in characterizing and engineering silicon dangling bond (DB)-based structures of relevance to nanoelectronic devices.
The scientists identified the single H atom functionalized tip through a unique signature in frequency shift vs displacement curves (i.e., Δf(z)) and a characteristic enhancement of STM images in filled and empty states.
By bringing the H-functionalized tip apex very close to a DB in the absence of bias and current, a covalent bond between the single hydrogen and silicon atoms is formed.
Subsequent changes in the STM images and Δf(z) curves confirmed that this mechanically induced reaction results in the passivation of the DB with the hydrogen from the tip apex.
"It has become clear that CO-functionalized tips are effective for characterization of adsorbed molecules on metal surfaces," the authors conclude their report. "It is clear also that accessible and effective tips are required for other systems of study. Preparing and identifying such a tip is described in this work. Moreover, the Hfunctionalized tip is shown to allow characterization and also induce changes in DB-based structures on the H-Si(100) surface through selective mechanically induced hydrogen passivation, or 'capping'."