摘要
Heterostructures based on two-dimensional(2D) transition-metal dichalcogenides(TMDCs) possess unique electronic and optical properties, which open up unprecedented opportunities in nanoscale optoelectronic devices. Synthesizing high-quality 2D TMDC heterostructures with different core/shell size ratios is of great significance for practical applications. Here, we report a simple one-step chemical vapor deposition(CVD) method for fabricating MoS2/WS2 lateral heterostructures with controllable core/shell size ratio. An ultrathin MoO3/WO3 film prepared by thermal evaporation was used as the precursor, and a step-like heating process was adopted to separately grow MoS2 and WS2 monolayers by taking advantage of the different melting points of MoO3 and WO3 sources. High-quality MoS2/WS2 lateral heterostructures with sharp interfaces were fabricated by optimizing the key growth parameters. Furthermore, the core/shell size ratio of heterostructures could be easily controlled by changing the thickness ratio of MoO3/WO3 film, and an approximately linear dependence between them is revealed. Compared with MoS2 or WS2 monolayers, the MoS2/WS2 heterostructure exhibited a shortened exciton lifetime owing to the type-Ⅱ energy band alignment, which is conducive to the application of high-performance devices. This work provides a facile strategy for the synthesis of 2D lateral heterostructures with controllable size ratio.
基金
supported by the National Natural Science Foundation of China (Grant Nos. 61974123, 61774128, 61874092, 11604275, 61704040
61804129)
National Science Fund for Excellent Young Scholars (Grant No. 62022068)
Natural Science Foundation of Fujian Province of China(Grant Nos. 2018I0017, and 2019H0002)
Natural Science Foundation of Jiangxi Province of China (Grant No. 20192BAB217013)
Science and Technology Key Projects of Xiamen (Grant No. 3502ZCQ20191001)
Fundamental Research Funds for the Central Universities (Grant Nos.20720190055, and 20720190058)。
