"Science Bulletin" Issue 1 of 2021 published a review article "Controllable Preparation and Potential Applications of Two-Dimensional Metallic Transition Metal Chalcogenides" written by Professor Zhang Yanfengs research group from the Department of Materials, School of Engineering, Peking University.

This article introduces the chemical vapor deposition preparation method of high-quality two-dimensional metallic transition metal chalcogenide materials. This method has realized the controllable preparation of material layer thickness, size, morphology and phase state; and then summarizes this kind of material. The research progress of materials in micro-nanoelectronic devices and electrocatalytic hydrogen evolution, etc., and summarizes and prospects for future development trends and challenges.



Two-dimensional metallic transition metal chalcogenides (MTMDCs) have rich and unique physical and chemical properties (such as superconductivity, charge density wave phase transition, magnetism, etc.), and have broad application prospects in the fields of electronic devices, energy storage and conversion, etc. .



How to obtain high-quality two-dimensional MTMDCs materials?



The chemical vapor deposition (CVD) method can take into account the preparation requirements of large area, large domain area, adjustable layer thickness, and high crystal quality. It can also be compatible with current semiconductor processes, so it has attracted wide attention.



In recent years, the research group of Professor Yanfeng Zhang of Peking University has made a series of research progress in the controllable preparation, basic physical properties and application exploration of two-dimensional MTMDCs materials.

Based on the CVD method, they successfully obtained 1T-VS2, 1T-VSe2 nanosheets with a layer thickness of a few nanometers and a domain size of tens of microns, and found that these two materials are constructed based on the field effect of single-layer semiconducting TMDCs. Ideal electrode material for transistor (FET) devices (Nano Lett, 2017, 17: 4908; Adv Mater, 2017, 29: 1702359);

At the same time, they prepared centimeter-scale uniform, high-quality few-layer TaS2 and single-layer TaSe2 films for the first time on gold foil, and studied the characteristics of their charge density wave (CDW) phase transition with layer thickness (Nat Commun, 2017, 8: 958; Adv Mater, 2018, 30: 1804616);

Subsequently, they realized the controllable preparation of 1T-TaS2 vertical nanosheet arrays on a three-dimensional porous gold substrate (Adv Mater, 2018, 30: 1705916), and the batch of high-quality MTMDCs (TaS2, V5S8, NbS2) nanosheet powders Prepared (J Am Chem Soc, 2019, 141: 18694), and explored its application in electrocatalytic hydrogen evolution;

In addition, they also successfully prepared large-area, high-quality, and environmentally stable single crystals of NiTe2 and VTe2, and proved that these two materials have high conductivity and have extremely high application prospects in the field of two-dimensional electronics/optoelectronics (ACS Nano, 2020, 14: 9011; ACS Nano 2021, DOI: 10.1021/acsnano.0c10250).



Based on the above results, Professor Zhang Yanfeng was invited to write a review article in the "Science Bulletin", systematically summarizing the CVD preparation methods and novel physical properties of two-dimensional MTMDCs materials, as well as its research progress in field effect transistors and electrocatalytic hydrogen evolution applications.







In terms of synthesis and physical property research, the article introduces in detail the preparation methods of two-dimensional MTMDCs nanosheets, large-area uniform film thickness, vertical orientation nanosheet arrays, and nanosheet powders, and analyzes two typical synthesis routes (one-step preparation method) And two-step preparation method) on the material layer thickness, domain size and geometric morphology, and the key influencing factors of each method. In addition, the article also briefly introduces the research progress and unsolved problems of the physical properties of two-dimensional MTMDCs such as CDW phase transition, superconductivity and magnetism.



In terms of application research, this paper summarizes in detail the construction and performance research of metallic-semiconductor TMDCs lateral heterojunction and vertical heterojunction FET devices; as well as the theoretical and experimental research on the electrocatalytic hydrogen evolution activity of MTMDCs. At the same time, it points out the challenges and development directions of the two research fields, and provides possible solutions.



In short, two-dimensional MTMDCs materials have rich physical properties, good electrical conductivity and catalytic performance, and it is expected that they will play a greater role in the future devices and energy fields.