Narrow Results

This paper provides a comprehensive review on the methodological development and technical applications of in situ microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM), developed in the last decade for investigating the structure-mechanical-property relationship of a single one-dimensional nanomaterial, such as nanotube, nanowire and nanobelt. The paper covers both the fundamental methods and detailed applications, including AFM-based static elastic and plastic measurements of a carbon nanotube, external field-induced resonance dynamic measurement of elastic modulus of a nanotube/nanowire, nano-indentation, and in situ plastic deformation process of a nanowire. Details are presented on the elastic property measurements and direct imaging of plastic to superplastic behavior of semiconductor nanowires at atomic resolution, providing quantitative information on the mechanical behavior of nanomaterials. The studies on the Si and SiC nanowires clearly demonstrated their distinct, "unexpected" and superior plastic mechanical properties. Finally, a perspective is given on the future of nanomechanics.

A novel approach in two-dimensional point probe electrical measurement in TEM is proposed to identify electrical properties at specific positions. This approach calls for a sharp W probe to be driven by piezo-motors in order to make contact with TEM samples and then proceeding I–V measurements are taken and then scanned with constant bias. The doping type and p–n junction interface can be identified by rectifying I–V data obtained. By applying this method to a transistor device with a 200 nm gate length, we could qualitatively distinguish the doping area from the substrate. Mapping results with scanning probe revealed a presence of a dopant spreading region 60 nm wide at the junction interface.