Academia Sinica

Tien T Tsong

Ing-Shouh Hwang

Hong-Shi Kuo

Tsu-Yi Fu

A method for preparing an iridium tip with atomic sharpness. The method includes tapering an iridium wire to a needle shape and heating the iridium needle in an oxygen atmosphere. Also disclosed is an iridium needle having a pyramidal structure which terminates with a small number of atoms prepared by the methods.

Atomically sharp iridium tip

This invention discloses an electrochemical method for the preparation of single atom tips to replace the traditional vacuum evaporation method. The invented method for preparation of single atom tips includes the following steps: A substrate single crystal metal wire etched electrochemically to form a tip. The surface of the metal tip is cleaned. A small quantity of noble metal is plated on the apex of the tip in low concentration noble metal electrolyte. Annealing in vacuum or in inert gas ambient to diffuse the additional electroplated noble metal atoms and thus a single atom tip is formed on the surface of the substrate. The present invention also discloses the single atom tip so prepared. The single atom tip of this invention has only a very small number of atoms, usually only one atom, at its apex.

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Kirkland, WA, United States of America

Tien T Tsong