Self‐Aligned and Scalable Growth of Monolayer WSe2–MoS2 Lateral Heterojunctions

2D layered heterostructures have attracted intensive interests due to their unique optical, transport, and interfacial properties. The laterally stitched heterojunction based on dissimilar 2D transition metal dichalcogenides forms an intrinsic p–n junction without the necessity of applying an external voltage. However, no scalable processes are reported to construct the devices with such lateral heterostructures. Here, a scalable strategy, two‐step and location‐selective chemical vapor deposition, is reported to synthesize self‐aligned WSe₂–MoS₂ monolayer lateral heterojunction arrays and demonstrates their light‐emitting devices. The proposed fabrication process enables the growth of high‐quality interfaces and the first successful observation of electroluminescence at the WSe₂–MoS₂ lateral heterojunction. The electroluminescence study has confirmed the type‐I alignment at the interface rather than commonly believed type‐II alignment. This self‐aligned growth process paves the way for constructing various 2D lateral heterostructures in a scalable manner, practically important for integrated 2D circuit applications.     

Metal‐Guided Selective Growth of 2D Materials: Demonstration of a Bottom‐Up CMOS Inverter

2D transition metal dichalcogenide (TMD) layered materials are promising for future electronic and optoelectronic applications. The realization of large‐area electronics and circuits strongly relies on wafer‐scale, selective growth of quality 2D TMDs. Here, a scalable method, namely, metal‐guided selective growth (MGSG), is reported. The success of control over the transition‐metal‐precursor vapor pressure, the first concurrent growth of two dissimilar monolayer TMDs, is demonstrated in conjunction with lateral or vertical TMD heterojunctions at precisely desired locations over the entire wafer in a single chemical vapor deposition (VCD) process. Owing to the location selectivity, MGSG allows the growth of p‐ and n‐type TMDs with spatial homogeneity and uniform electrical performance for circuit applications. As a demonstration, the first bottom‐up complementary metal‐oxide‐semiconductor inverter based on p‐type WSe₂ and n‐type MoSe₂ is achieved, which exhibits a high and reproducible voltage gain of 23 with little dependence on position.     

The Sympathetic Nervous System Contributes to the Establishment of Pre-Metastatic Pulmonary Microenvironments

Emerging evidence suggests that neural activity contributes to tumor initiation and its acquisition of metastatic properties. More specifically, it has been reported that the sympathetic nervous system regulates tumor angiogenesis, tumor growth, and metastasis. The function of the sympathetic nervous system in primary tumors has been gradually elucidated. However, its functions in pre-metastatic environments and/or the preparation of metastatic environments far from the primary sites are still unknown. To investigate the role of the sympathetic nervous system in pre-metastatic environments, we performed chemical sympathectomy using 6-OHDA in mice and observed a decrease in lung metastasis by attenuating the recruitment of myeloid-derived suppressor cells. Furthermore, we note that neuro-immune cell interactions could be observed in tumor-bearing mouse lungs in conjunction with the decreased expression of Sema3A. These data indicate that the sympathetic nervous system contributes to the preparation of pre-metastatic microenvironments in the lungs, which are mediated by neuro-immune cell interactions.     

Porosity-controlled multilayer TaC coatings prepared via wet powder process for multi-functional reactor components in GaN crystal growth system

Multilayer TaC coatings with layers of different porosities, that provide corrosion resistance and controlled wettability against molten metal are prepared via a wet powder process and a subsequent sintering process. A porous TaC top layer with a dense TaC underlayer formed on a graphite substrate is applied as a reactor component. It is found that this layer significantly increases the surface area of a molten Ga source via capillary action due to its high open porosity. It is also demonstrated that this layer enhances the Ga vapor supply rate, and thus the growth rate, during halogen-free vapor-phase epitaxial growth of GaN crystals.     

Induced chirality through electromagnetic coupling between chiral molecular layers and plasmonic nanostructures

We report a new approach for creating chiral plasmonic nanomaterials. A previously unconsidered, far-field mechanism is utilized which enables chirality to be conveyed from a surrounding chiral molecular material to a plasmonic resonance of an achiral metallic nanostructure. Our observations break a currently held preconception that optical properties of plasmonic particles can most effectively be manipulated by molecular materials through near-field effects. We show that far-field electromagnetic coupling between a localized plasmon of a nonchiral nanostructure and a surrounding chiral molecular layer can induce plasmonic chirality much more effectively (by a factor of 10(3)) than previously reported near-field phenomena. We gain insight into the mechanism by comparing our experimental results to a simple electromagnetic model which incorporates a plasmonic object coupled with a chiral molecular medium. Our work offers a new direction for the creation of hybrid molecular plasmonic nanomaterials that display significant chiroptical properties in the visible spectral region.     

Experimental and computational study on sintering of ceramic coating layers with complex porous structures

This study investigated the sintering behavior of an yttria-stabilized zirconia coating for thermal barrier coatings (TBCs) with a complicated porous structure via both experiment and simulation using the finite element method for samples with only a coating (free coating) and samples with coating on a substrate (constrained coating). Sintering and grain growth proceeded from the bottom of the coating, and the coating bent convex upward in the free coating. In the constrained coating, sintering and grain growth proceeded in a manner similar to the free coating; however, the degrees of sintering and grain growth were small. Furthermore, sintering and grain growth were delayed because of substrate constraints. As a simulation result, the free coating was bent in a manner similar to the experiment. The experimental results could be reproduced in terms of time dependency and temperature dependency. The decrease in the porosity of the constrained coating was delayed compared with that in the free coating because of substrate constraints. This simulation result was able to reproduce the experimental results. Thus, the sintering behavior for the complex porous structures of TBCs can be predicted by experimental research and simulation, which could aid in the development of a prediction technology for the delamination of coatings (TBC lifetime).     

Clustering triple microbeads in a dynamic microarray for timing-controllable bead-based reactions

In this study, we developed a dynamic microfluidic device that enables the clustering of three different types of microbeads in a trapping spot and the rearrangement of contacting modes of the clustered microbeads. To achieve these two functions, two features are added to the conventional dynamic microfluidic device. (1) To trap multiple beads, an extended trapping spot with sub-by-pass channels and a valve was employed. (2) To rearrange the clustered microbeads, trapping spots that work only by backward flow were added. The design of the microfluidic device was realized by calculations based on fluidic resistance. By using the designed device, we successfully clustered different types of hydrogel microbeads including target materials, and observed reactions between clustered microbeads. In addition, by rearranging the contacting modes of the clustered microbeads, the reaction could be initiated/terminated at the desired time. We found that this dynamic microfluidic device is applicable to the quantitative analysis of chemical reactions between small amounts of multiple materials.