A Novel Heating Technology for Ultra-High Resolution Imaging in Electron Microscopes

Allard, Lawrence F., Wilbur C. Bigelow, Steven A. Bradley and Jingyue “Jimmy” Liu, 2009
Atmosphere in situ TEM holder and manifold
Image courtesy of Microscopy Today

Abstract

Capabilities for in-situ studies of materials at elevated temperatures and under gaseous environments have received increasing attention in recent years [1]. With the advent of electron microscopes that provide routine imaging at the atomic level (e.g. aberration-corrected TEM and STEM instruments), it is of particular interest to be able to record images at high temperatures while retaining the inherent resolution of the microscope; that is, the resolution is not limited by drift in the heating holder or other instabilities associated with its operation. A number of commercial and experimental heating devices have been used over the years; some holders are designed with miniature furnaces that heat entire grids [2], while a more recent development used a tiny spiral filament coated with a carbon film as the heater element [3]. These devices, while very useful for some applications (particularly in “environmental microscopes” that employ differential pumping to allow gases at some elevated pressure to be injected around the specimen), are invariably not as stable as might be desired for sub-Ångström imaging experiments. They are also limited by the speed at which the sample can be heated to temperature for stable operation. In collaboration with Protochips Inc. (Raleigh, NC), our laboratory is developing a novel new technology for in-situ heating experiments that overcomes a number of performance problems associated with standard heating stage technologies [4].

Impact Statement

The development of a new technology for in situ heating experiments that can record images at high temperatures without compromising the microscope’s resolution. Previously developed devices have proved to be limited by the sample’s speed at reaching a stable operation temperature. They also lack the required stability for subÅngström imaging. In creating their new device, the researchers seek to solve both these and other problems currently faced by those using present technology.