In situ Electromechanical Probing in a TEM

Laboratory Directed Research and Development

Andrew M. Minor

The goal of this project is to establish the technical ability to probe both the electrical and mechanical properties of individual nanostructures simultaneously, quantitatively and at high resolution in a TEM. This capabiltity would enable the study of coupled electrical and mechanical phenomena for a wide variety of materials science applications, including energy scavenging, microstructural evolution in piezoresistive materials, phase transformations during mechanical deformation and exploratory work on individual nanostructures.

The research and development efforts will center around the design and initial implementation of a custom-built holder for a transmission electron microscope. The holder will have the sensitivity and stability for in situ TEM electromechanical probing of individual nanostructures such as piezoresistive thin films or nanowires. To date, one of the main limitations on bending or compression experiments of individual nanowires below ~100nm in diameter have come from control of the testing apparatus and the noise floor for quantitative force data. The stability and control of quantitative mechanical testing has come a long way in the past few years, and new control electronics have just become available that will allow for improved displacement control and feedback in order to decrease the current amount of vibration in the indenter tip. Accurate displacement control is important for in situ small-scale mechanical testing where one would like to anticipate contact and deformation in terms of a spatial constraint (the field of view during the test).