title: Single-Crystal Diamond Nanowire Tips for Ultrasensitive Force Microscopy.
abstract: We report the fabrication, integration, and assessment of sharp diamond tips for ultrasensitive force microscopy experiments. Two types of tips, corresponding to the upper and lower halves of a diamond nanowire, were fabricated by top-down plasma etching from a single-crystalline substrate. The lower, surface-attached halves can be directly integrated into lithographically defined nanostructures, like cantilevers. The upper, detachable halves result in diamond nanowires with a tunable diameter (50-500 nm) and lengths of a few microns. Tip radii were around 10 nm and tip apex angles around 15°. We demonstrate the integration of diamond nanowires for use as scanning tips onto ultrasensitive pendulum-style silicon cantilevers. We find the noncontact friction and frequency jitter to be exceptionally low, with no degradation in the intrinsic mechanical quality factor (Q ≈ 130,000) down to tip-to-surface distances of about 10 nm. Our results are an encouraging step toward further improvement of the sensitivity and resolution of force-detected magnetic resonance imaging.
authors.affiliation: Department of Physics, ETH Zurich , 8093 Zurich, Switzerland.|Department of Chemistry, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Y
authors.initials: Y
authors.lastname: Tao
authors.affiliation: Department of Physics, ETH Zurich , 8093 Zurich, Switzerland.
authors.forename: C L
authors.initials: CL
authors.lastname: Degen
keywords: Single-crystal diamond; nanofabrication; nanomechanics; nanowire; noncontact friction; ultrasensitive force microscopy