单层MoS2(1-x)Se2x合金材料中硒原子的晶界择优掺杂和富集

摘要

采用球差校正扫描透射电子显微镜(STEM)研究化学气相沉积法制备的二维MoS2(1-x)Se2x合金材料中Se元素掺杂、取代的微观过程和机理.定量和统计STEM表征结果发现:Se原子晶界处富集显著,晶界处Se元素含量远高于晶畴内部.进一步研究表明晶界中掺杂取代Se原子的浓度和分布与晶界结构密切相关.主要与晶界处的局域畸变及其诱导的反应活性有关.该结果对于二维过渡金属硫族化物合金体系的可控合成及应用拓展具有重要意义.%We report a microscopic study on the process for the substitution of selenium into monolayer molybdenum disulfide via a joint CVD-STEM characterization.Results from quantitative and statistic STEM reveal that the concentration of Se atoms in grain boundaries is much higher than that in intra-domains of monolayer MoS2(1-x)Se2x alloy.In-depth analysis finds that Se atoms are enriched in the distorted regions due to presence of dislocation cores on the grain boundary,which can be further understood by considering the difference of chemical reactivity for doping reaction in different types of grain boundaries with different symmetry and different misorientation angles.Our results pave the way towards the controlled growth of alloyed two-dimensional transition metal dichalcogenide materials with a high precision,and their further applications.