Ion-beam sculpting at nanometre length scales.
Manipulating matter at the nanometre scale is important for many electronic, chemical and biological advances, but present solid-state fabrication methods do not reproducibly achieve dimensional control at the nanometre scale. Here we report a means of fashioning matter at these dimensions that uses low-energy ion beams and reveals surprising atomic transport phenomena that occur in a variety of materials and geometries. The method is implemented in a feedback-controlled sputtering system that provides fine control over ion beam exposure and sample temperature. We call the method "ion-beam sculpting", and apply it to the problem of fabricating a molecular-scale hole, or nanopore, in a thin insulating solid-state membrane. Such pores can serve to localize molecular-scale electrical junctions and switches and function as masks to create other small-scale structures. Nanopores also function as membrane channels in all living systems, where they serve as extremely sensitive electro-mechanical devices that regulate electric potential, ionic flow, and molecular transport across cellular membranes. We show that ion-beam sculpting can be used to fashion an analogous solid-state device: a robust electronic detector consisting of a single nanopore in a Si3N4 membrane, capable of registering single DNA molecules in aqueous solution.
Li
J
J
Department of Physics Harvard University, Cambridge, Massachusetts 02138, USA.
Stein
D
D
McMullan
C
C
Branton
D
D
Aziz
M J
MJ
Golovchenko
J A
JA
D015374:Biosensing Techniques; D004247:DNA / Q000302:isolation & purification*; D005374:Filtration / Q000379:methods; D007477:Ions; D008567:Membranes, Artificial; D008832:Microchemistry / Q000379:methods*; D008904:Miniaturization; D008956:Models, Chemical; D017655:Silicon Compounds
D007477:Ions; D008567:Membranes, Artificial; D017655:Silicon Compounds; D004247:DNA; C032734:silicon nitride