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Fabrication of Metallized Nanopores in Silicon Nitride Membranes for Single‐Molecule Sensing
Author(s) -
Wei Ruoshan,
Pedone Daniel,
Zürner Andreas,
Döblinger Markus,
Rant Ulrich
Publication year - 2010
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201000253
Subject(s) - nanopore , materials science , silicon nitride , membrane , fabrication , silicon , nanotechnology , nitride , transmission electron microscopy , raman spectroscopy , characterization (materials science) , optoelectronics , optics , chemistry , medicine , biochemistry , alternative medicine , physics , pathology , layer (electronics)
Abstract The fabrication and characterization of a metallized nanopore structure for the sensing of single molecules is described. Pores of varying diameters (>10 nm) are patterned into free‐standing silicon nitride membranes by electron‐beam lithography and reactive ion etching. Structural characterization by transmission electron microscopy (TEM) and tomography reveals a conical pore shape with a 40° aperture. Metal films of Ti/Au are vapor deposited and the pore shape and shrinking are studied as a function of evaporated film thickness. TEM tomography analysis confirms metalization of the inner pore walls as well as conservation of the conical pore shape. In electrical measurements of the transpore current in aqueous electrolyte solution, the pores feature very low noise. The applicability of the metallized pores for stochastic sensing is demonstrated in real‐time translocation experiments of single λ‐DNA molecules. We observe exceptionally long‐lasting current blockades with a fine structure of distinct current levels, suggesting an attractive interaction between the DNA and the PEGylated metallic pore walls.