Scanning transmission electron characteristics

Figure 17.3.2 Detection limits, sampling depth, and spot size for several surface spectroscopic techniques. XRP (x-ray fluorescence) EMP (electron microprobe) EEL (electron energy loss), SAM (scanning Auger microprobe) STEM (scanning transmission electron microscopy). Other abbreviations in Figure 17.3.1. This figure is meant to provide a graphic summary of the relative capabilities of different methods modem instmments have somewhat better quantitative performance characteristics than the 1986 values given here. [From A. J. Bard, Integrated Chemical Systems, Wiley, New York, 1994, pp. 103, with permission adapted from Texas Instmments Materials Characterizations Capabilities, Texas Instmments, Richardson, TX, 1986, with permission.]...

Principles and Characteristics In the late 1960s an alternative to the TEM imaging geometry was introduced by Crewe et al. [239], who used similar optics to produce a very small electron probe that was scanned in a raster over the area of interest. This high-resolution scanning transmission electron microscope (STEM) has become an... 

Table 5.28. Main characteristics of scanning transmission electron microscopy (STEM)...

Because of the instrumental requirements, these are usually not routine monitoring techniques. However, unlike other methods, they give detailed information on particle shapes. In addition, chemical composition information can be obtained using transmission electron microscopy (TEM) or scanning electron microscopy (SEM) combined with energy-dispersive spectrometry (EDS). The electron beam causes the sample to emit fluorescent X-rays that have energies characteristic of the elements in the sample. Thus a map showing the distribution of elements in the sample can be produced as the electron beam scans the sample. 

Transmission electron microscopy (TEM) has traditionally been the mainstay of morphological investigations of polyolefins [8], but recent developments in low voltage high-resolution field emission gun scanning electron microscopy (FEG-SEM) [9] and the advent of atomic force microscopy (AFM) and related near-field techniques [10] have challenged its dominance at the length scales of the order of 10 nm, characteristic of both microdeformation (cavitation, fibrils) and structural components of semicrystalline... 

The use of high-resolution transmission electron microscopy (HRTEM) and scanning tunneling microscopy (STM) to investigate the morphologies of oxides and chlorides and to compare the surface characteristics of dispersed materials, films, and single crystals. 

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