Coherent nano‐area electron diffraction

Abstract

We describe the new coherent nano-area electron diffraction (NED) and its application for structure determination of individual nanostructures. The study is motivated by the challenge and the general lack of analytical techniques for characterizing nanometer-sized, heterogeneous phases. We show that by focusing electrons on the focal plane of the pre-objective lens using a 3rd condenser lens and a small condense aperture, it is possible to achieve a nanometer-sized highly parallel illumination or probe. The high angular resolution of diffraction pattern from the parallel illumination allows over-sampling and consequently the solution of phase problem based on the recently developed ab initio phase retrieval technique. From this, a high-contrast and high-resolution image can be reconstructed at resolution beyond the performance limit of the image-forming objective lens. The significance of NED for nanostructure characterization will be exemplified by single-wall carbon nanotubes and small metallic clusters. Imaging from diffraction patterns, or diffractive imaging, will be demonstrated using double-wall carbon nanotubes.

Probing Interfacial Electronic Structures in Atomic Layer LaMnO3 and SrTiO3 Superlattices

“…The superlattice structure was quantified using nanoarea electron diffraction. [24] An example of the superlattice nanoarea electron diffraction pattern is shown in Figure 1c. A diffraction pattern was also recorded from the STO substrate near the superlattice (not shown) and used for calibration.…”

Structural Characteristics of Ternary InxGa1–xAs Nanowires on Si (111) Grown via Au-Catalyzed VLS

“…The existence of massive stacking faults also can be inferred from the streaky lines in the ED patterns. 16 Despite massive stacking faults, no misfit dislocation can be found in the NWs (Fig. 3(d)).…”

TEM based high resolution and low-dose scanning electron nanodiffraction technique for nanostructure imaging and analysis

“…Transmission electron diffraction (TED) is an appropriate technique for complex nanostructure analysis because it is highly sensitive to local structure and it can be obtained using a small electron beam (Cowley, 1993;Spence and Zuo, 1992;Zuo et al, 2003Zuo et al, , 2004. Compared to the scanning electron microscope (SEM) based electron backscattering diffraction technique, the small interaction volume in TED allows for high spatial resolution.…”

“…Using this technique, Cowley demonstrated electron nanodiffraction for a number of interesting samples at resolution of 1 nm or less. In modern TEM instruments, a parallel electron beam of nanometers in diameter can be obtained with help of an additional condenser lens (minilens) (Zuo et al, 2003(Zuo et al, , 2004. In a field emission gun (FEG) TEM, the small beam gives excellent coherent diffraction patterns.…”