Simultaneous Hosting of Positive and Negative Trions and the Enhanced Direct Band Emission in MoSe2/MoS2 Heterostacked Multilayers

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• 作者：Min Su Kim ; Changwon Seo ; Hyun Kim ; Jubok Lee ; Dinh Hoa Luong ; Ji-Hoon Park ; Gang Hee Han ; Jeongyong Kim
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：June 28, 2016
• 年：2016
• 卷：10
• 期：6
• 页码：6211-6219
• 全文大小：511K
• 年卷期：0
• ISSN：1936-086X

文摘

Heterostacking of layered transition-metal dichalcogenide (LTMD) monolayers (1Ls) offers a convenient way of designing two-dimensional exciton systems. Here we demonstrate the simultaneous hosting of positive trions and negative trions in heterobilayers made by vertically stacking 1L MoSe₂ and 1L MoS₂. The charge transfer occurring between the 1Ls of MoSe₂ and MoS₂ converted the polarity of trions in 1L MoSe₂ from negative to positive, resulting in the presence of positive trions in the 1L MoSe₂ and negative trions in the 1L MoS₂ of the same heterostacked bilayer. Significantly enhanced MoSe₂ photoluminescence (PL) in the heterostacked bilayers compared to the PL of 1L MoSe₂ alone suggests that, unlike other previously reported heterostacked bilayers, direct band transition of 1L MoSe₂ in heterobilayer was enhanced after the vertical heterostacking. Moreover, by inserting hexagonal BN monolayers between 1L MoSe₂ and 1L MoS₂, we were able to adjust the charge transfer to maximize the MoSe₂ PL of the heteromultilayers and have achieved a 9-fold increase of the PL emission. The enhanced optical properties of our heterostacked LTMDs suggest the exciting possibility of designing LTMD structures that exploit the superior optical properties of 1L LTMDs.