Controlling the surface functionality of nanomaterials

A New Approach to the Habit Determination of Nano-Objects by SEM

“…A spatial resolution that makes it possible to solve metrological problems for nano-objects is provided by scanning probe methods, transmission electron microscopy and SEM [10,11]. Scanning probe methods enable one to measure details of a relief several tens of nanometres in height (for example, arrays of quantum dots) with an Ångström accuracy, and to determine the shape of nano-objects or etch figures.…”

“…For this purpose, it is necessary to determine the crystallographic indices of projections, which can be realized in scanning electron microscopes equipped with detectors for recording Kikuchi maps that arise in electron backscatter diffraction (the EBSD method). These maps make it possible to identify the crystal structure of the object under observation, which is necessary, in particular, to ensure ecological monitoring [11].…”

“…Transmission electron microscopy makes it possible to determine the crystallographic characteristics of nano-objects and to examine their habit with the use of stereomicroscopy [13]. High-resolution electron microscopy methods ensure an Ångström accuracy of measurements [11,14]. However, although transmission electron microscopy is a promising method for characterizing arrays of nanoobjects [11], its limiting resolution is suited only for layers with a thickness close to or less than 10 nm, which, in turn, has limited its application to objects with a relief height ≥ 10 nm [14].…”

“…High-resolution electron microscopy methods ensure an Ångström accuracy of measurements [11,14]. However, although transmission electron microscopy is a promising method for characterizing arrays of nanoobjects [11], its limiting resolution is suited only for layers with a thickness close to or less than 10 nm, which, in turn, has limited its application to objects with a relief height ≥ 10 nm [14]. In a number of cases, the interpretation of nano-object images invites theoretical investigation of the contrast [14][15].…”

“…First, properties of nano-objects are anisotropic, the objects themselves can have a complex shape and an adequate explanation of their properties requires the knowledge of their sizes along different crystallographic directions. Second, in order to ensure ecological safety, it is necessary to determine the habit of nanoparticles and the relevant numerical characteristics, i.e., relative fractions of faces of different types [9][10][11].…”