Laser-induced phenylation reaction to prepare semiconducting single-walled carbon nanotube arrays

Strong Room-Temperature Ferromagnetism of MoS2 Compound Produced by Defect Generation

Ferromagnetic materials have been attracting great interest in the last two decades due to their application in spintronics devices. One of the hot research areas in magnetism is currently the two-dimensional materials, transition metal dichalcogenides (TMDCs), which have unique physical properties. The origins and mechanisms of transition metal dichalcogenides (TMDCs), especially the correlation between magnetism and defects, have been studied recently. We investigate the changes in magnetic properties with a variation in annealing temperature for the nanoscale compound MoS2. The pristine MoS2 exhibits diamagnetic properties from low-to-room temperature. However, MoS2 compounds annealed at different temperatures showed that the controllable magnetism and the strongest ferromagnetic results were obtained for the 700 °C-annealed sample. These magnetizations are attributed to the unpaired electrons of vacancy defects that are induced by annealing, which are confirmed using Raman spectroscopy and electron paramagnetic resonance spectroscopy (EPR).

Selected-Area Fabrication of a Single-Walled Carbon Nanotube Schottky Junction with Tunable Gate Rectification

Single-walled carbon nanotube (SWNT)-based devices are expected to play an important role in the next generation of electronic integrated circuits. As an important structural unit for SWNT-based electronics, the Schottky junction has a series of functions such as rectification, photoelectric detection, switching, etc. Here, we demonstrate a well-controlled localized radical reaction method to prepare an intramolecular SWNT Schottky junction with a closed edge. This junction exhibits strong gate-dependent rectifying behavior and a high rectification ratio of 962. Furthermore, the semiconducting part on the junction side could be effectively tuned from p-type doping to n-type doping, resulting in reversible rectifying behavior. Our work paves a new avenue for the design and synthesis of an SWNT Schottky junction, which is very important to future applications for carbon-based nanoelectronic devices.

Toward an Intelligent Synthesis: Monitoring and Intervening in the Catalytic Growth of Carbon Nanotubes

The bottom-up approach to directly synthesizing low-dimensional materials with outstanding performance has extended the material basis for the next generation integrated circuit industry. All the low-dimensional semiconductors, metals, dielectrics, and their heterojunctions are very promising bricks to build faster and more efficient chips because of their atomically smooth surface and interfaces. The greatest challenge in the synthesis of nanomaterials is how to precisely control the structure, crystalline orientation, defects, dimensions, etc. In past decades, both the methodology and the mechanism of synthesis have been systematically investigated to improve the controllability. However, few studies focused on sensing the synthesis processes in situ and responding to the synthesis immediately. Here, we propose the concept of intelligent synthesis in which the final product can be automatically fine-controlled by a closed loop including in situ monitoring and real-time interventions. As a model system, a high-temperature-tolerant circuit is fabricated on the single-walled carbon nanotube (SWCNT) growth substrate for sensing and responding to the synthesis processes. As a result, either highly pure semiconducting (s-) SWCNT arrays or metallic-semiconducting (m-s) junction arrays with different junction positions is simply synthesized by programming the responding signal. The intelligent synthesis shows much higher efficiency and controllability compared to conventional methods and will lead to the next leap in nanotechnology.