Chemical vapor deposition merges MoS2 grains into high-quality and centimeter-scale films on Si/SiO2

Self-Expansion Based Multi-Patterning for 2D Materials Fabrication beyond the Lithographical Limit

Two-dimensional (2D) materials are promising successors for silicon transistor channels in ultimately scaled devices, necessitating significant research efforts to study their behavior at nanoscopic length scales. Unfortunately, current research has limited itself to direct patterning approaches, which limit the achievable resolution to the diffraction limit and introduce unwanted defects into the 2D material. The potential of multi-patterning to fabricate 2D materials features with unprecedented precision and low complexity at large scale is demonstrated here. By combining lithographic patterning of a mandrel and bottom-up self-expansion, this approach enables pattern resolution one order of magnitude below the lithographical resolution. In-depth characterization of the self-expansion double patterning (SEDP) process reveals the ability to manipulate the critical dimension with nanometer precision through a self-limiting and temperature-controlled oxidation process. These results indicate that the SEDP process can regain the quality and morphology of the 2D material, as shown by high-resolution microscopy and optical spectroscopy. This approach is shown to open up new avenues for research into high-performance, ultra-scaled 2D materials devices for future electronics.

Realization of low potential barrier in MoS2/rGO heterojunction with enhanced electrical conductivity for thin film thermoelectric applications

Two-dimensional (2D) van der Waals materials in-plane anisotropy, caused by a low-symmetric lattice structure, has considerably increased their applications, particularly in thermoelectric. MoS2and MoS2/reduced graphene oxide (rGO) thin films were grown on SiO2/Si substrate by atmospheric chemical vapor deposition technique to study the thermoelectric performance. Few layered MoS2was confirmed by the vibrational analysis and the composition elements are confirmed by the x-ray photoelectron spectroscopy technique. The continuous grains lead to reduced phonon life time in A1gand low activation energy assists to enhance the electrical property. The MoS2/rGO has achieved the highestσof 22 622 S m-1at 315 K due to an electron-rich cloud around the electrons in S atoms near the adjacent layer of rGO.

Three-Dimensional Electrochemical Sensors for Food Safety Applications

Considering the increasing concern for food safety, electrochemical methods for detecting specific ingredients in the food are currently the most efficient method due to their low cost, fast response signal, high sensitivity, and ease of use. The detection efficiency of electrochemical sensors is determined by the electrode materials' electrochemical characteristics. Among them, three-dimensional (3D) electrodes have unique advantages in electronic transfer, adsorption capacity and exposure of active sites for energy storage, novel materials, and electrochemical sensing. Therefore, this review begins by outlining the benefits and drawbacks of 3D electrodes compared to other materials before going into more detail about how 3D materials are synthesized. Next, different types of 3D electrodes are outlined together with common modification techniques for enhancing electrochemical performance. After this, a demonstration of 3D electrochemical sensors for food safety applications, such as detecting components, additives, emerging pollutants, and bacteria in food, was given. Finally, improvement measures and development directions of electrodes with 3D electrochemical sensors are discussed. We think that this review will help with the creation of new 3D electrodes and offer fresh perspectives on how to achieve extremely sensitive electrochemical detection in the area of food safety.

Two-Dimensional Material-Based Electrochemical Sensors/Biosensors for Food Safety and Biomolecular Detection

Two-dimensional materials (2DMs) exhibited great potential for applications in materials science, energy storage, environmental science, biomedicine, sensors/biosensors, and others due to their unique physical, chemical, and biological properties. In this review, we present recent advances in the fabrication of 2DM-based electrochemical sensors and biosensors for applications in food safety and biomolecular detection that are related to human health. For this aim, firstly, we introduced the bottom-up and top-down synthesis methods of various 2DMs, such as graphene, transition metal oxides, transition metal dichalcogenides, MXenes, and several other graphene-like materials, and then we demonstrated the structure and surface chemistry of these 2DMs, which play a crucial role in the functionalization of 2DMs and subsequent composition with other nanoscale building blocks such as nanoparticles, biomolecules, and polymers. Then, the 2DM-based electrochemical sensors/biosensors for the detection of nitrite, heavy metal ions, antibiotics, and pesticides in foods and drinks are introduced. Meanwhile, the 2DM-based sensors for the determination and monitoring of key small molecules that are related to diseases and human health are presented and commented on. We believe that this review will be helpful for promoting 2DMs to construct novel electronic sensors and nanodevices for food safety and health monitoring.