The FIB approach to the nanofabrication of devices for in-situ TEM studies of nanostructures

In the recent years dual beam focused ion beam (FIB), consisting in an ion column coupled to an electron column (SEM) has demonstrated to be a powerful tool for the manipulation of nanostructures and nanodevices[1,2]. The study of the physical properties of single nanostructures in combination with in situ high spatial resolution electron microscopy, promises to be of great benefit for basic and applied research in nanoscience. For this purpose, in situ transmission electron microscopy (TEM) can be used for ultrahigh spatial resolution [3]. In the present work we aim to realize electrode devices by FIB that allow for an in situ TEM study of a single nanostructure while performing current transport experiments. The aim of the experiment is to study the morphology and structure of a single nanostructure with the TEM while these are biased by an external voltage and their I-V characteristics are recorded. Such an experiment puts extremely high demands on the specimen: free standing electrode structures have to be fabricated in a device structure that can be electrically contacted under stable conditions, whilst the device has to be transparent for the TEM imaging. We fabricated a TEM specimen holder with four electrode pairs that can be connected to the specimen holder and where the nanogap and the transparent region was realized by FIB processes.