Synthesis of monolayer tungsten nitride:Rapid optical visualization and electrical impact of grain boundaries  

作　　者：Qiuyun Yang Dehu Li Fanfan Shi Zhibin Shao Na Wang Yao Peng Edwin Hang Tong Teo Zheng Liu Hong Wang 

机构地区：[1]Department of Physics,University of Science and Technology of China,Hefei 230026,China [2]Institute of Electrical and Electronic Engineering,Anhui Science and Technology University,Fengyang 233100,China [3]College of Mechanics and Engineering Science,Hohai University,Nanjing 211100,China [4]School of Materials Science and Engineering,Nanyang Technological University,50 Nanyang Avenue,Singapore 639798,Singapore

出　　处：《Nano Research》2025年第3期645-653,共9页纳米研究(英文版)

基　　金：supported by the National Natural Science Foundation of China(Nos.12104434 and 62074051);the Scientific Research Foundation of the Higher Education Institutions of Anhui Province,China(Nos.2022AH051648 and 2024AH040057)。

摘　　要：Two-dimensional(2D)transition metal nitrides(TMNs)have garnered significant attention in fields such as energy storage and nanoelectronics due to their unique electrical properties,high chemical stability,and excellent mechanical strength.In polycrystalline 2D TMNs films,grain boundaries(GBs)are inevitable structural defects that could play a crucial role in determining the material's properties.Developing rapid optical visualization methods is essential for obtaining large-scale information on the distribution of GBs.However,the rapid visualization of GBs in 2D TMNs,as well as the impact of GBs on the material's electrical properties,has never been previously reported.In this study,we demonstrate the growth of monolayer tungsten nitride crystals on SiO_(2)/Si substrates by chemical vapor deposition(CVD).High-resolution transmission electron microscopy reveals the presence of GBs at the junctions of twisted grains.A wet-etch process utilizing buffered oxide etchant(BOE)enables rapid and effective visualization of these GBs with optical microscopy.By analyzing grains with different twist angles,we find that GBs at specific angles demonstrate increased stability during etching.Electrical measurements revealed that tilted GBs hinder electrical transport,with GBs of a 62°twist angle showing sheet conductance nearly half that within the monolayer grain.This work not only provides insights into GBs in monolayer tungsten nitride but also lays the groundwork for exploring GBs-related properties in other 2D TMNs.

关 键 词：two-dimensional(2D)materials grain boundary chemical vapor deposition electrical property tungsten nitride 

分 类 号：O43[机械工程—光学工程]