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The transmission electron microscope (TEM) is a powerful imaging, diffraction and spectroscopy tool that has revolutionized the field of microscopy. It has contributed to numerous breakthroughs in various scientific disciplines. TEM-based techniques can offer atomic resolution as well as elemental analysis, which benefit the study of epitaxial semiconductors and their related optoelectronic devices on the atomic scale. The design and optimization of the device performance depend on three key factors: the control of strain at nanometer scale, control of the formation and propagation of defects as well as the control of local electronic properties. Manipulation and optimization are only possible if the key factors can be characterized precisely. Herein, the TEM techniques for strain analysis, defect characterization and bandgap evaluation are reviewed and discussed. Lately, with the development of in-situ TEM techniques, researchers have been able to observe dynamic processes and study the behaviour of materials and devices under realistic conditions (in gaseous atmosphere or in liquids, at elevated or cryogenic temperatures, under strain, bias or illumination) in real-time with extremely high spatial resolution. This review explores the impact and significance of in-situ TEM in the field of semiconductors. [ABSTRACT FROM AUTHOR]

How to form functional materials has long been the cornerstone in materials physics and chemistry, which stimulates general materials scientists to eagerly explore a variety of physicochemical methods toward fabricating desirable materials. In materials formation, constituent elements undergo related phase transitions from atoms/ions/molecules to colloids, nanocrystals, microcrystals, powders/films, or bulk single crystals. These phase transition processes dramatically limit a series of materials' characteristics/features/performances, such as structures, sizes, morphologies, and properties/functions. In this paper, the formation of materials is uncovered from the viewpoint of multiscale crystallization, from both theoretical studies and experimental observations. The entire crystallization process includes both nucleation and crystal growth stages, respectively controlling the involved phase transitions among clusters/materials with multiscale features. Taking some typical materials as examples, we illustrated the dominant role of variable materials status with multiple sizes during crystallization processes in their practical applications toward energy storage and sustainability. The compromise/coupling between thermodynamics and kinetics controls variant factors to span multiscale modes during materials formation. Uncovering materials physics and chemistry from the viewpoint of multiscale crystallization may deepen our understanding in materials formation in the micro/mesoscale size range and facilitate function optimizations. [ABSTRACT FROM AUTHOR]

Changes in the surrounding environment, if transmitted to the electron microscope, are frequently perceived as noise that diminishes the quality of the images. However, in fact, 'noises' contain rich information about the environment. This work reports a very rare event where aberration-corrected HAADF-STEM images were acquired during the impact of seismic waves, resulted from a mild earthquake. By analysing these images, we found that the drift and vibration of the sample are detectable and quantifiable. Despite many potential challenges, this work demonstrates the utilisation of electron microscopes in detecting and monitoring seismic waves with high spatial resolution, which may lead to unique applications in the low-frequency regime., (© 2024 Royal Microscopical Society.)