A pathway to structure-property relationship for future nanowire-based energy harvesting and electronic devices. In-situ experiments are performed to simultaneously probe the electrical and mechanical behavior of nanowire specimens. Atomistic modeling gives fundamental insights into the behavior of matter at the nanoscale. The two approaches are integrated to give a complete picture of the mechanical, electrical and electromechanical properties of nanowires.

One dimensional nanostructures, nanowires and nanotubes, are envisioned as building blocks for future nanoelectronic devices. They exhibit remarkable mechanical properties such as high strength and increased elastic modulus. Furthermore, electromechanical-coupling effects like piezoelectricity and piezoresistivity are also enhanced at the nanoscale. Our research focuses on single nanowire studies of metallic and semiconducting nanowires. Using state-of-the-art experimental and computational techniques we probe the mechanical, electrical and electromechanical properties of materials such as gallium nitride (GaN), zinc oxide (ZnO), gold (Au) and silver (Ag). Experimental results from in-situ TEM testing and insights from atomistic simulations are combined to give a complete picture across a broad range of sizes and structures of the fundamental causes of size-effects in material properties. The fundamental results from our research should pave the way for applications of these materials in new-generation electrical interconnects, nanostructured materials and energy-harvesting devices.

Specific projects include:

1. In-Situ Electromechanical Testing. In-situ electromechanical testing in the Transmission Electron Microscope (TEM) using MEMS-based technology is used to relate material properties with atomic structure.
2. Atomistic modeling. Multiscale QM/MD (Quantum Mechanics / Molecular Dynamics) modeling is employed to analyze size effects in mechanical and electromechanical properties of semiconducting nanowires.
3. Piezoelectric Nanowires for Energy Harvesting. Electromechanical coupling in individual nanowires is probed using quantum mechanics simulations and a novel nano-Electromechanical Testing System with the purpose of developing design criteria for future energy harvesting devices.