Rigid tip improves atomic force microscopy

Abstract

Atomic force microscopy (AFM) can get chemists pretty close to actually seeing the atoms and bonds of molecules. The technique produces images a bit like a record player generates sound. An atomic-scale needle at the end of a cantilevered arm scans across a sample, moving up and down according to the shape and electronic properties of the surface. Measuring and recording that deflection produces a three-dimensional representation of the molecules within the sample. Minimizing interactions between the needle and the sample can lead to sharper images. In 2009, IBM researchers proposed using a carbon monoxide tip to significantly improve AFM resolution. The drawback is that atoms on a sample’s surface can tug on the CO dangling from the end of a metal needle, making bonds look longer than they actually are or creating artifacts that look like bonds between atoms. Now, researchers have swapped this flexible CO tip for a