Beam damage is a major limitation in electron microscopy that becomes increasingly severe at higher resolution. One possible route to circumvent radiation damage, which forms the basis for single-particle electron microscopy and related techniques, is to distribute the dose over many identical copies of an object. For the acquisition of low-dose data, ideally no dose should be applied to the region of interest before the acquisition of data. We present an automated approach that can collect large amounts of data efficiently by acquiring images in a user-defined area-of-interest with atomic resolution. We demonstrate that the stage mechanics of the Nion UltraSTEM, combined with an intelligent algorithm to move the sample, allow the automated acquisition of atomically resolved images from micron-sized areas of a graphene substrate. Moving the sample stage automatically in a regular pattern over the area-of-interest enables the collection of data from pristine sample regions without exposing them to the electron beam before recording an image. Therefore, it is possible to obtain data with minimal dose (no prior exposure during focusing), which is only limited by the minimum signal needed for data processing. This enables us to minimize beam-induced damage in the sample and to acquire large data sets within a reasonable amount of time.

The unique one-dimensional electronic and optical properties attributed to single-walled carbon nanotubes (SWCNTs) are mainly related to the peculiar local arrangement of sp2 hybridised carbon atoms. This structural configuration gives raise to interesting features, which can be identified with various spectroscopic techniques. In the case of SWCNTs, high energy spectroscopy methods represent effective key tools to analyse the modifications of the underlying basic correlation effects in the bonding environment, the charge transfer between functionalized nanotubes, and on-wall doping. More specifically, in this article we review the shape of the C1s photoemission (PES) response related to the density of states (DOS) of the valence band (VB) in SWCNTs and its changes upon on-wall functionalization and metallicity-sorting. In the last, the progress in the identification of changes in the site selective valence-band electronic structure is clarified in detail.