Herein, we report the synthesis and characterization of a novel class of polymer composites based on onion-like carbons (OLCs)-silicon diimide by a salt-free polycondensation reaction. The pyridine-catalyzed polymerization reaction was carried out in the presence of various contents (0.1, 0.5, 1, and 2 wt%) of carboxyl-functionalized OLCs in argon atmosphere to provide composites with well-dispersed and covalently incorporated 0D nanocarbons throughout the 3D matrix of silicon diimide polymer. A strong dependency of the optical properties (UV absorbance and the photoluminescence spectra) on the content of functionalized OLCs incorporated within the polymer matrix was observed. The novel polymer composites are suitable precursors for the design of advanced and multifunctional 0D-nanocarbon–containing Si3N4-based ceramic nanocomposites.

Although the concept, first demonstration, and potential applications of X-ray transmission mirrors (XTMs) were initially described over 30 years ago, only a few implementations exist in the literature. This is attributed to the unsolved challenge of a thick frame supporting a thin, reflecting membrane which does not itself block the transmitted beam. Here, we introduce a novel approach to solve this problem by employing silicon microfabrication. A robust XTM frame has been fabricated by using a novel two-step etch process, which secures the thin-film membrane without blocking the transmitted beam. Specifically, we have fabricated delicate XTM optics with 90% yield, which consist of 280-nm-thick low-stress silicon nitride membrane windows that are 1.5 mm wide and 125 mm long on silicon substrates. The XTM optics have been demonstrated to be a more efficient high-pass X-ray filter; for example, when configured for 40% transmission of 11.3 keV photons, we measure the reduction of 8.4 keV photons by a factor of 56.

Understanding the fundamental properties of macromolecules has enhanced the development of emerging technologies used to improve biomedical research. Currently, there is a critical need for innovative platforms that can illuminate the function of biomedical reagents in a native environment. To address this need, we have developed an in situ approach to visualize the dynamic behavior of biomedically relevant macromolecules at the nanoscale. Newly designed silicon nitride devices containing integrated “microwells” were used to enclose active macromolecular specimens in liquid for transmission electron microscopy imaging purposes.We were able to successfully examine novel magnetic resonance imaging contrast reagents, micelle suspensions, liposome carrier vehicles, and transcribing viral assemblies. With each specimen tested, the integrated microwells adequately maintained macromolecules in discrete local environments while enabling thin liquid layers to be produced.

An in situ electron energy loss spectroscopy (EELS) technique has been developed to investigate the dynamic processes associated with electron-beam nanofabrication on thin membranes. In this article, practical applications germane to e-beam nanofabrication are illustrated with a case study of the drilling of nanometer-sized pores in silicon nitride membranes. This technique involves successive acquisitions of the plasmon-loss and the core-level ionization-loss spectra in real time, both of which provide the information regarding the hole-drilling kinetics, including two respective rates for total mass loss, individual nitrogen and silicon element depletion, and the change of the atomic bonding environment. In addition, the in situ EELS also provides an alternative method for endpoint detection with a potentially higher time resolution than by imaging. On the basis of the time evolution of in situ EELS spectra, a qualitative working model combining knock-on sputtering, irradiation-induced mass transport, and phase separation can be proposed.

A 1/2[0001](0001) stacking fault and a planar 60° rotational domain boundary on the (0001) plane in as-grown CVD α-Si3N4 crystals have been characterized by high-resolution electron microscopy and image simulation. As reported previously, two types of coherent boundaries have been observed in this material, namely, stacking faults and rotational domain boundaries. The former involves only a translational displacement, while the latter separates two grains by a 60° rotation in addition to a translation. Inasmuch as the difference resulting from the rotational component can hardly be detected by high-resolution electron microscopy, care must be taken to analyze them first by analytical electron microscopy. In this paper, these two types of boundaries are studied and structural models are constructed that give simulated images in satisfactory agreement with observed images.