We report on the observation of the strain-induced oriented alignment of graphene layers during the in situ 80 keV e-beam irradiation of an amorphous carbon structure using an aberration corrected (Cs-corrected) electron transmission microscope. E-beam irradiation promoted the amorphous-to-ordered structure transformation and contributed to the formation of small sized graphene flakes by local structure reconstruction. In the mean time, graphene flakes were driven to rotate and re-orient along the strain direction under the uni-axial stress conditions, which finally connected with each other and produced a high oriented structure. Our observations suggest that strain engineering could be an effective method in tuning the microstructure and properties especially in layer-structured materials.

We report here a nano-electronic–mechanical storage mechanism with graphene flakes (GFs) revealed by in situ transmission electron microscopy observations accompanied by nano-manipulation and probing of electrical properties. Repeatable two- and three- level state storage was demonstrated using two GFs nanoelectrodes with evident hysteresis properties. The detailed mechanisms, including the formation and rupture of the GFs contact as well as the corresponding electrical properties of the hysteresis, were visualized directly. Due to the high mechanical stability and outstanding electrical conductivity of the graphene, the hysteresis property is quite stable, which allows multi-value storage in this system. This work provides a route to achieve multiple value storage based on the nano-electronic–mechanical storage mechanism.

Graphene–CNT (G/CNT) hybrids were formed via in situ joule heating inside a transmission electron microscope (TEM). The formation of the G/CNT structure was suggested to be induced by the sequential and spontaneous unzipping of the outmost wall of the multi-walled CNT under uniformly thermal etching and voltage pulse of 0.2–1 V. The conductance of the G/CNT hybrids show a significantly change (up to 38 times) after decorated with CdTe quantum dots. Our results suggest the potential use of the G/CNT hybrids for high-sensitivity detections, as well as super capacitors or catalyst matrices given their large specific surface areas.

In this work, we performed detailed in situ TEM observations of the rapid encapsulation and release of lithium in nanometric structures under e-beam irradiation. With fast kinetics, the e-beam irradiation induced the formation of a LiCl shell due to the surface reaction between lithium and the surrounding chloride. In parallel, a rapid lithium release from the LiCl surface shell underwent as a competitive process. The detailed dynamic encapsulation and releasing processes were revealed with enhanced time and spatial resolution. Lithium nanoparticles, nanorods and Li/LiCl core–shell nanoparticles and nanotubes were observed during these processes. Due to the important application of lithium materials in the energy storage field, where lithium encapsulation and releasing processes play the fundamentally important roles, our findings may trigger new application methods for lithium based energy storage, in which e-beam irradiation may be used to enhance the ultra-rapid energy harvesting or releasing process.

It is found that surface energy plays the dominant role in direct e-beam etching of single crystal ZnO and ITO nanostructures through a surface etching (sputtering) process, especially for electron energies smaller than the characteristic energy for bulk atoms knock-off. This mechanism can be used for the fabrication of sub-10 nm hierarchical structures on single crystal nanostructure precursors. We performed detailed in situ HRTEM observations of the surface energy guided etching (SEGE) process on ZnO nanowires. The etching of (0001) crystal planes, that have the lowest surface energy, was found to dominate the etching process. It is also shown that the SEGE mechanisms can be extended to single crystal ITO nanowires for sub-10 nm hierarchical structure fabrication. The hierarchical structures fabricated by the SEGE process show increased specific surface areas (SSA), which may be useful in fields such as sensors, catalysts and solar cells.

We report on the observation of the strain-induced oriented alignment of graphene layers during the in situ 80 keV e-beam irradiation of an amorphous carbon structure using an aberration corrected (Cs-corrected) electron transmission microscope. E-beam irradiation promoted the amorphous-to-ordered structure transformation and contributed to the formation of small sized graphene flakes by local structure reconstruction. In the mean time, graphene flakes were driven to rotate and re-orient along the strain direction under the uni-axial stress conditions, which finally connected with each other and produced a high oriented structure. Our observations suggest that strain engineering could be an effective method in tuning the microstructure and properties especially in layer-structured materials.