title: Double-tilt in situ TEM holder with multiple electrical contacts and its application in MEMS-based mechanical testing of nanomaterials.
abstract: MEMS and other lab-on-a-chip systems are emerging as attractive alternatives to carry out experiments in situ the electron microscope. However, several electrical connections are usually required for operating these setups. Such connectivity is challenging inside the limited space of the TEM side-entry holder. Here, we design, implement and demonstrate a double-tilt TEM holder with capabilities for up to 9 electrical connections, operating in a high-resolution TEM. We describe the operating principle of the tilting and connection mechanisms and the physical implementation of the holder. To demonstrate the holder capabilities, we calibrate the tilting action, which has limits of ±15°, and establish the insulation resistance of the electronics to be 36GΩ, appropriate for measurements of currents down to the nano-amp (nA) regime. Furthermore, we demonstrate tensile testing of silver nanowires using a previously developed MEMS device for mechanical testing, using the implemented holder as the platform for electronic operation and sensing. The implemented holder can potentially have broad application to other areas where MEMS or electrically-actuated setups are used to carry out in situ TEM experiments.
authors.affiliation: Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Bernal
authors.affiliation: Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA; Department of Theoretical and Applied Mechanics, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Rajaprakash
authors.initials: R
authors.lastname: Ramachandramoorthy
authors.affiliation: Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA; Department of Theoretical and Applied Mechanics, Northwestern University, Evanston, IL 60208, USA; iNfinitesimal LLC, Skokie, IL 60077, USA. Electronic address: espinosa@northwestern.edu.
authors.forename: Horacio D
authors.initials: HD
authors.lastname: Espinosa
keywords: Capacitive sensing; Electromechanical properties; JEOL 2100; Nanowires