Applied Physics

Reflecting Atoms off Graphene

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Science  16 Dec 2011:
Vol. 334, Issue 6062, pp. 1473-1475
DOI: 10.1126/science.334.6062.1473-e

Electron and ion microscopes can provide exquisite structural detail on the nano- and subnanometer scale. However, achieving such resolution requires that the charged particles be accelerated to high energy, which can lead to structural damage induced by the scattering particles. There is also a requirement that the sample surface be conducting so that charging effects can be avoided. The scattering of low-energy neutral atoms or molecules can also be used to obtain structural information at high resolution, obviating the restrictions of sample conductivity and induced damage. The neutral beams of particles can in principle be guided by mirrors, but the problem is then being able to identify and fabricate high-quality atom mirrors. Sutter et al. report that terminating a typical atom mirror (consisting of a ruthenium layer deposited on sapphire) with a single layer of graphene considerably improves the reflectivity of helium atoms and hydrogen molecules from the surface. The flexibility of graphene facilitates self-molding of the material to any surface contours and corrugations and should enable the fabrication of complex, perhaps even reconfigurable, atom optic elements that would allow the operation of a scanning helium atom or hydrogen molecule microscope.

Appl. Phys. Lett. 99, 211907 (2011).

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