High spatiotemporal-resolution imaging in the scanning transmission electron microscope

Abstract

AbstractThe temporal resolution in scanning transmission electron microscopy (STEM) is limited by the scanning system of an electron probe, leading to only a few frames per second (fps) at most in the current microscopes. To push the boundary of atomic-resolution STEM imaging into dynamic observations, an unprecedentedly faster scanning system combined with fast electron detection systems should be a prerequisite. Here we develop a new scanning probe system with the acquisition time of 83 nanoseconds per pixel and the fly-back time of 35 microseconds, leading to 25 fps STEM imaging with the image size of 512 × 512 pixels that is faster than a human perception speed. Using such high-speed probe scanning system, we have demonstrated the observations of shape-transformation of Pt nanoparticles and Pt single atomic motions on TiO2 (110) surface at atomic-resolution with the temporal resolution of 40 milliseconds. The present probe scanning system opens the door to use atomic-resolution STEM imaging for in situ observations of material dynamics under the temperatures of cooling or heating, the atmosphere of liquid or gas, electric-basing or mechanical test.