Karsten Kunze

Dynamic phenomena at the micro‐ and nanoscale underpin technologies ranging from micro‐ and nanoelectromechanical systems (MEMS/NEMS) actuators and sensors to quantum instrumentation and communication hardware. In this paper, we demonstrate that time‐resolved full‐field scanning electron microscopy (SEM) for periodically driven micro‐ and nanostructures offers access to their spatiotemporal dynamics. This is achieved using a conventional SEM operated with its continuous electron beam and combined with a multi‐channel plate (MCP) with a time‐to‐digital converter (TDC) for time‐resolved measurements. Effective frame rates from to frames per second are reached and motion tracking with nm spatial and ns temporal jitter is demonstrated, enabling access to both micrometer‐scale and nanometer‐scale motion. By bringing high temporal resolution to widely available electron microscopes without invasive column modifications, this approach enables a broad range of experiments on dynamic micro‐ and nanomechanical systems.

Quantifying the intrinsic properties of 2D materials is of paramount importance for advancing their applications. Large‐scale production of 2D materials merits the need for approaches that provide direct information about the role of growth substrate on 2D material properties. Transferring the 2D material from its growth substrates can modify the intrinsic properties of the asgrown 2D material. In this study, suspended chemical vapor deposition (CVD) graphene films are prepared directly on their growth substrates in a high‐density grid array. The approach facilitates the quantification of intrinsic strain and doping in suspended CVD graphene films. To achieve this, transmission electron microscopy and large‐area Raman mapping are employed. Remarkably, the analysis reveals consistent patterns of compressive strain (≈−0.2%) both in the diffraction patterns and Raman maps obtained from these suspended graphene films. By conducting investigations directly on the growth substrates, the potential influences introduced during the transfer process are circumvented effectively. Consequently, the methodology offers a robust and reliable means of studying the intrinsic properties of 2D materials in their authentic form, uninfluenced by the transfer‐induced alterations that may skew the interpretation of their properties.

Crystal orientation-dependent etching, charge-carrier trapping behaviour, and performance of single-crystal photocathodes are enabled by ammonia solution etching of thermally-oxidised Cu₂O.

An unprecedented approach is introduced to compositionally map binder-containing Li-X zeolite sorbents at various stages of the industrial manufacture.

Nano-heteroepitaxial growth of GaAs on Si(001) by metal organic vapor phase epitaxy was investigated to study emerging materials phenomena on the nano-scale of III–V/Si interaction. Arrays of Si nano-tips (NTs) embedded in a SiO ₂ matrix were used as substrates. The NTs had top Si openings of 50–90 nm serving as seeds for the selective growth of GaAs nano-crystals (NCs). The structural and morphological properties were investigated by high resolution scanning electron microscopy, atomic force microscopy, electron backscatter diffraction, x-ray diffraction, and high resolution scanning transmission electron microscopy. The GaAs growth led to epitaxial NCs featuring a bi-modal distribution of size and morphology. NCs of small size exhibited high structural quality and well-defined {111}–{100} faceting. Larger clusters had less regular shapes and contained twins. The present work shows that the growth of high quality GaAs NCs on Si NTs is feasible and can provide an alternate way to the integration of compound semiconductors with Si micro- and opto-electronics technology.