scanning tunneling microscope

noun

1. a device that uses a moving needle and the tunnel effect to generate a maplike image of the atomic surface structure of matter, thereby achieving even greater magnification than the scanning electron microscope.

scanning tunneling microscope

1. A microscope used to make images of individual atoms on the surface of a metal. The microscope has a probe with a small voltage applied to it ending in a tiny sharp tip (ideally consisting of one atom) that is moved close the material's surface. Quantum tunneling of electrons between tip and the metal provides a small current, and that current is held constant by varying the distance between the tip and the material's surface atoms. As the probe is moved across the surface, a three-dimension image of the surface is formed, based on the continual adjustments made to the height of the tip to keep the electron flow constant.