Nanometric Scale Biosample Observation Using a Photon Scanning Tunneling Microscope

Abstract

A T4 bacteriophage with a tail diameter of about 9 nm was observed for the first time in an atmospheric condition without a metal film coating, by means of a superresolution photon scanning tunneling microscope (PSTM) using a fiber probe. Fiber probes with cone angles of 25°-100° and their minimum curvature radii less than 10 nm were fabricated andthe angle variance was less than 0.5°. The normal resolution of such a PSTM was evaluated to be less than 1 nm, and the lateral resolution, limited by the curvature radius of the fiber probe, was estimated to be within 20 nm.